SAWAFUJI ELECTRIC CO.,LTD.0957-600-3700

201006#0

FRAME & GENERATOR

SHOP MANUAL

Y-TYPE

CONTENTS SHT25D-Y

1. SPECIFICATIONS

1-1. SPECIFICATIONS ………………………………………………………………………………………….2

1-2. PERFORMANCES ……………………………………………………………………………………….3

1-3. DIMENSIONAL DRAWINGS ……………………………………………………………………………………..4

1-4. WIRING DIAGRAM …………………………………………………………………………………………5

2. SERVICE INFORMATIONS

2-1. SAFETY PRECAUTIONS ………………………………………………………………………………6

2-2. ELECTRICAL PRECAUTIONS ……………………………………………………………………….6

2-3. MAINTENANCE STANDARDS

2-3-1. GENERATOR RESISTANCE …………………………………………………………………………7

2-3-2. ENGINE ……………………………………………………………………………………..8-10

2-3-3. TIGHTENING TORQUES ………………………………………………………………………………….11

2-4. AVR ……………………………………………………………………………………………….12

2-5. CHANGE OG FREQUENCY ………………………………………………………………………………….13

3. TROUBLESHOOTING

3-1. GENERATOR

3-1-1. EVIDENT PHYSICAL DEFECTS ……………………………………………………………………………….14

3-1-2. VOLTAGE FAULTS ……………………………………………………………………………..15

3-1-3. ENGINE CIRCUIT TROUBLESHOOTING …………………………………………………………16-18

3-2. ENGINE ………………………………………………………………………………………..19-21

4. DISASSEMBLY AND SERVICING

4-1. EXTERNAL COMPONENT …………………………………………………………………………22

4-2. GENERATOR …………………………………………………………………………………….23

4-3. SERVICING ……………………………………………………………………………..24-27

- 1 -- 1 -- 1 -- 1 -

1. SPECIFICATIONS SHT25D-Y

1-1. SPECIFICATIONS

YFrequency 50 Hz

Output 20 kVA (16kW)

Voltage 415 V

Amps 27.8 A

Power factor

Type

No. of phase

No. of poles

Voltage reg. system

Insulation class

Coupling

Model

Design

No. of sylinders

Bore × Stroke

Displacement

JIS D0006 21.2(28.8) kW(PS)/1500 rpm

JIS D8014 18.4(25.0) kW(PS)/1500 rpm

Governor regulation

Combustion system

Fuel injection pump

Governor

Nozzle

Injection timing

Injection pressure

Compression ratio

Lubricating system

Lubricating filter

Lubricating oil

Lubricating oil capacity

Fuel oil

Fuel tank capacity

Cooling system

Coolant capacity

Fan type

Flywheel type

Flywheel housing type

Starting system

Starting support device

Dynamo for charging

Direction of rotation

Battery (V ×Ah/5Hr)

Volt meter

Ampere meter

Frequency meter

Hour meter

Warning lights

Output

ATS terminal

Terminal

Weight (dry)

Yes

No

Yes

Indicator lights (4-conditions)

Yes

Yes

Accessary

545 kg

- 2 -- 2 -- 2 -- 2 -

Continuous output

87 × 92.4 mm

2,197 cc

SAE No.4

Less than 5 %

Spherical type (New T.V.C.S : Three Voltex Combustion system)

Bosch "Mini" type

Mechanical governer

SHT25D

0.8

Three

Generator

Engine

Rated

Rated output

Rotating-field, brush-less, self-excitation system, AC generator

4

AVR

H

Coupling disc;SAE#7.5(offset disc) Flange adaptor;SAE#4

V2203-B-BGSE-1

Vertical, liquid,cooled, 4-cycle, diesel engine

4

Bosch "Throttle" type

0.30 to 0.33 rad. (17 to 19°) before T.D.C.

13.73 Mpa, 140 kgf/cm2, 1991 psi

23 : 1

Pusher type

SAE No.7-1/2

Forced lubricating by trochoid pump

Cartridge type (full flow paper filter)

Quality better than CD class

7.6 L

Diesel fuel No.2-D (ASTMD975)

72 L

Water cooling with water pump

8.1 L

Electric starting with starter (12 V, 1.4 kw)

By glow plug in combustion chamber

Counterclockwise (from flywheel side)

80D26R (12V-55Ah)

12 V , 480 w

SHT25D-Y

1-2. PERFORMANCES

Transient %

Stedy %

Recovery time sec

Voltage stability %

Transient %

Stedy %

Recovery time sec

Frequency stability %

Insulation resistance Mohm

Wave-form distortion %

Circuit protector capacity A

Insulation class ---

Fuel consumption (full load) lit./h

Continuous operable hours (3/4 load) h

Fuel tank capacity lit.

Sound level (7m) dB(A)

- 3 -- 3 -- 3 -- 3 -

ModelSHT25D

less than 30

less than +/-2.5

less than 5

less than +/-1

less than 10

less than 7

less than 8

Voltage

regulation

Frequency

regulation

less than +/-0.5

more than 10

66

H

72

Y

less than 5

29

less than 5.8

more than 17.6

SHT25D-Y

1-3. DIMENSIONAL DRAWINGS

- 4 -- 4 -- 4 -- 4 -

1660mm690mm

900mm

SHT25D-Y

1-4. WIRING DIAGRAM

- 5 -- 5 -- 5 -- 5 -

< SHT25D-Y >

　

2. SERVICE INFORMATION SHT25D-Y

2-1. SAFETY PRECAUTIONS

•Read the instructions before you begin, and be sure you have the tools and skills

required to perform the tasks safely.

•Be sure that the engine is off before you begin any maintenance or repairs.

This will reduce the possibility of several hazards:

Carbon monoxide poisoning from engine exhaust. Be sure there is adequate ventilation whenever you run the engine.

Burns from hot parts. Let the engine cool before you touch it.

Injury from moving parts. Do not run the engine unless the instruction tells you to do so. Even then, keep your

hands, fingers, and clothing away.

•To reduce the possibility of a fire or explosion, be sure when working around fuel.

Use only a nonflammable solvent, not fuel, to clean parts.

Keep all cigarettes, sparks, and flames away from all fuel-related parts.

2-2. ELECTRIC PRECAUTIONS

1) Check the connector terminals for bend, excessive extrusion, missing terminal,

or other abnormalities before connecting the connector.

2) To connect, insert the connector as full as it goes.

3) Check the connector cover for breakage and check whether the connector

female terminal is not open excessively. Then, connect the connector securely.

4) Clamp the wire harnesses securely so that they do not interfere with the rotating

parts, moving parts and the hot parts.

5) Route and connect the wire harnesses properly. Be sure that the harnesses are

not slack, twisted or pulled taut.

6) Take care not to pinch the wire harnesses during installation of a part.

7) Read the tester manufacturer's operation instructions carefully before operation

with a tester.

- 6 -- 6 -- 6 -- 6 -

SHT25D-Y

2-3. MAINTENANCE STANDARDS

2-3-1. GENERATOR

(A) Resistance

< SHT25D > (at 20℃)

Item Mesuring part Resistance value (ohm)

Main stator Internal terminal 0.36

0.36

0.36

at disconnection U1-U2 U5-U6

V1-V2 V5-V6

W1-W2 W5-W6

EBG 3P connector 12.9

Excitor stator --- 18.5

Exciter rotor --- 0.23

Main rotor --- 0.66

(B) Others < SHT25D >

0.18

---

Wiring symbol

(each winding)

each terminal

F1-F2(from stator)

U-O

V-O

W-O

- 7 -- 7 -- 7 -- 7 -

Circuit protector capacity

Bearing

Weight

Type-Y ; 29 A

6306 2RS

116 kg

SHT25D-Y

2-3-2. ENGINE

(A) Engine Body

Factory specification Allowable limit

Cylinder head surface flatness - 0.05 mm

Top clearance 0.55 - 0.70 mm -

Thickness of gasket free 1.30 - 1.40 mm -

tightened 1.15 - 1.25 mm -

Compression pressure 3.53 - 3.72 Mpa -

36 - 38 kgf/cm2

Variance among cylinders - 10% or less

Valve clearance (cold) 0.18 - 0.22 mm -

Valve seat width (In/Ex) 2.12 mm -

Valve seat angle (In) 1.047 rad. (60°) -

angle (Ex) 0.785 rad. (45°) -

Valve face angle (In) 1.047 rad. (60°) -

angle (Ex) 0.785 rad. (45°) -

Valve recessing protrusion 0.05 mm

recess 0.15 mm

Valve stem to Valve guide clearance 0.040 - 0.070 mm -

Valve stem O.D. 7.960 - 7.975 mm -

Valve guide I.D. 8.015 - 8.030 mm -

Valve timing (Intake valve) open 0.21 rad. (12°) -

before T.D.C.

close 0.63 rad. (36°) -

after B.D.C.

Valve timing (Exhaust valve) open 1.05 rad. (60°) -

before T.D.C. -

close 0.21 rad. (12°) -

after B.D.C.

Valve spring free length 41.7 - 42.2 mm 41.2 mm

setting load 117.6 N 100.0 N

12.0 kgf 10.2 kgf

setting length 35.0 mm 35.0 mm

tilt - 1.0 mm

Rocker arm shaft to Rocker arm clearance 0.016 - 0.045 mm 0.15 mm

Rocker arm shaft O.D. 13.973 - 13.984 mm -

Rocker arm I.D. 14.000 - 14.018 mm -

Tappet to Tappet guide bore clearance 0.020 - 0.062 mm 0.07 mm

Tappet to Tappet guide bore O.D. 23.959 - 23.980 mm -

Tappet guide bore I.D. 24.000 - 24.021 mm -

Camshaft side clearance 0.07 - 0.22 mm 0.3 mm

Camshaft aligment - 0.01 mm

Cam henght In/Ex 33.47 mm 33.42 mm

Camshaft journal to Cylinder block bore oil clearance 0.050 - 0.091 mm 0.15 mm

Camshaft journal O.D. 39.934 - 39.950 mm -

Camshaft bearing I.D. 40.000 - 40.025 mm -

0.4 mm

- 8 -- 8 -- 8 -- 8 -

Item

SHT25D-Y

(A) Engine Body (continued)

Factory specification Allowable limit

Timing gear

Crank shat to Idle gear backlash 0.0415 - 0.1122 mm 0.15 mm

Idle gear to Cam gear backlash 0.0415 - 0.1154 mm 0.15 mm

Idle gear to Injection pump gear backlash 0.0415 - 0.1154 mm 0.15 mm

Crank gear to Oil pump drive gear backlash 0.0415 - 0.1090 mm 0.15 mm

Idle gear side clearance 0.20 - 0.51 mm 0.9 mm

Idle gear shaft to Idle gear bushing clearance 0.021 - 0.079 mm 0.10 mm

Idle gear bushing I.D. 28.000 - 28.021 mm -

Idle gear shaft O.D. 27.967 - 27.980 mm -

Piston pin bore I.D. 25.000 - 25.013 mm 25.05 mm

Piston pin clearance second ring 0.093 - 0.120 mm 0.20 mm

oil ring 0.020 - 0.052 mm 0.15 mm

Ring gap top ring 0.30 - 0.45 mm 1.25 mm

second ring 0.30 - 0.45 mm 1.25 mm

oil ring 0.25 - 0.45 mm 1.25 mm

Connecting rod aligment - 0.05 mm

Piston pin to Small end bushing clearance 0.014 - 0.038 mm 0.15 mm

Piston pin O.D. 25.002 - 25.011 mm -

Small end bushing I.D. 25.025 - 25.040 mm -

Crankshaft aligment - 0.02 mm

Crankshaft journal to Crankshaft bearing 1 oil clearance 0.04 - 0.118 mm 0.2 mm

Crankshaft journal O.D. 51.921 - 51.940 mm -

Crankshaft bearing 1 I.D. 51.980 - 52.025 mm -

Crankshaft journal to Crankshaft bearing 2 oil clearance 0.04 - 0.104 mm 0.2 mm

Crankshaft journal O.D. 51.921 - 51.940 mm -

Crankshaft bearing 2 I.D. 51.980 - 52.025 mm -

Crank pin to Crankpin bearing oil clearance 0.025 - 0.087 mm 0.2 mm

Crank pin O.D. 46.959 - 46.975 mm -

Crankpin bearing I.D. 47.000 - 47.046 mm -

Crankshaft clearance 0.15 - 0.31 mm 0.5 mm

Cylinder bore I.D. 87.000 - 87.022 mm +0.15 mm

Oversized cylinder liner I.D. +0.5 mm +0.15 mm

Item

- 9 -- 9 -- 9 -- 9 -

SHT25D-Y

(B) Lubricating System

Factory specification Allowable limit

Engine oil pressure at idle speed 98 kPa 49 kPa

1.0 kgf/cm2 0.5 kgf/cm2

at rated speed 294.2 - 441 kPa 245 kPa

3.0 - 4.5 kgf/cm2 2.5 kgf/cm2

Inner rotor to Outer rotor clearance 0.03 - 0.14 mm -

Outer rotor to Pump body clearance 0.11 - 0.19 mm -

Inner rotor to Cover end clearance 0.105 - 0.150 mm -

(C) Cooling Syatem

Thermostat's valve opening temperature 69.5 - 72.5 ℃ -

Temperature at whitch thermostat completelt opens 85 ℃ -

Radiator water tightness water tightness at -

specified pressure

137 kPa (1.4 kgf/cm2) -

Radiator cap air leakage pressure 10 seconds or more -

falling time 0.988 → 59 kPan2 -

0.6 → 0.9 kgf/cm2 -

Fan belt tension 10 - 12 mm/10kgf -

(D) Fuel System

Injection pump injection timing 0.30 - 0.33 rad. -

(17 - 19　°)

before T.D.C.

Pump element fuel tightness - 14.7 Mpa

150 kgf/cm2

Delivery valve fuel tightness more 10 seconds 5 seconds

14.7 → 13.7 Mpa 14.7 → 13.7 Mpa

150 → 140 kgf/cm2 150 → 140 kgf/cm2

Fuell injection nozzle injection 13.73 → 14.71 Mpa -

pressure 140 → 150 kgf/cm2

Fuell injection nozzle valve seat fuel tightness when the pressure is -

12.75 Mpa (130 kgf/cm2),

the valve seat must be

fuel tightness.

(E) Electrical System

Starter / Commutator O.D. 30.0 mm 29.0 mm

Starter / Mica undercut 0.5 - 0.8 mm 0.2 mm

Starter / Brush length 15.0 mm 10.0 mm

Alternator / Output current 14 V, 35 A/4000rpm -

Alternator / Rotor coil resistance 4 ohm -

Alternator / Slip ring O.D. 32.5 mm 32.1 mm

Alternator / Brush length 12.5 mm 5.5 mm

Glow plug / Resistance 0.8 ohm -

- 10 -- 10 -- 10 -- 10 -

Item

SHT25D-Y

2-3-3. TIGHTENING TORQUES

(A) for Special use

N-m kgf-m

Generator Coupling disc securing screw 75 7.6

Rotor mounting bolt 19.6 - 27.4 2.0 - 2.8

End bracket mounting screw 34.3 - 44.1 3.5 - 4.5

Engine Head cover cap nat 6.9 - 8.8 0.7 - 0.9

Nozzle holder 49.0 - 68.6 5.0 - 7.0

# Rocker arm bracket nut 23.5 - 27.5 2.4 - 2.8

# Head bolt 93.2 - 98.0 9.5 - 10.0

Fan drive oulley mounting nut 137.3 - 156.9 14.0 - 16.0

# Connecting rod bolt 44.1 - 49.0 4.5 - 5.0

# Flywheel bolt 98.0 - 108.0 10.0 - 11.0

# Bearing case bolt 1 46.1 - 50.9 4.7 - 5.2

# Bearing case bolt 2 68.6 - 73.5 7.0 - 7.5

Injection pipe retaining nut 19.6 - 24.5 2.0 - 2.5

Starter "B" terminal nut 8.8 - 11.8 0.9 - 1.2

Canopy Oil drain bolt 28.4 - 33.4 2.9 - 3.4

Note ; For "#"marked bolt and nut on the table, apply engine oil to their thereads and seatt before tightening.

(B) for General use

kgf-m

0.8 - 1.2

2.0 - 2.8

3.5 - 4.5

5.5 - 7.0

2.0 - 2.8

- 11 -- 11 -- 11 -- 11 -

Section Item

No-grade or 4T

N-m

M6

M8

M10

M12

Size

Grade

5/16-18

7.8 - 11.8

19.6 - 27.4

34.3 - 44.1

53.9 - 68.6

19.6 - 27.4

SHT25D-Y

2-4. AVR

ADJUSTMENT OF AVR CONTROLES

- 12 -- 12 -- 12 -- 12 -

VOLTAGE ADJUSTMENT

The generator output voltage is set at the factory, but can

be altered by careful adjustment of the VOLTS control on

the AVR board.

CAUTION Do not increase the voltage above the rated

generator voltage. If in doubt, refer to the rating label

attached on the canopy.

CAUTION Do not ground any of the hand trimmer

terminals as these could be above earth potential. Failure

to observe this could cause equipment damage.

If a replacement AVR has been fitted or re-setting of the

VOLTS adjustment is required, proceed as follows:

CAUTION

1. Before running generator, turn the VOLTS control fully

anti-clockwise.

2. Turn STABILITY control to midway position.

3. Start generator set, and run on no load at nominal

frequency e.g. 52-53Hz or 62-63Hz.

4. If the red Light Emitting Diode (LED) is illuminated, refer

to the Under Frequency Roll Off (UFRO) adjustment.

5. Carefully turn VOLTS control clockwise until rated

voltage is reached.

6. If instability is present at rated voltage, refer to stability

adjustment, then re-adjust voltage if necessary.

7. Voltage adjustment is now complete.

STABILITY ADJUSTMENT

The correct setting of the Stability adjustment can

be found by running the generator at no load and

slowly turning the stability control anti-clockwise

until the generator voltage starts to become

unstable.

The optimum or critically damped position is slightly

clockwise from this point (i.e. where the machine

volts are stable but close to the unstable region).

UNDER FREQUENCY ROLL OFF (UFRO)

ADJUSTMENT

The red Light Emitting Diode (LED) gives indication

that the UFRO circuit is operating.

The UFRO adjustment is preset and sealed and

only requires the selection of 50Hz / 60Hz using the

jumper link.

For optimum setting, the LED should illuminate as

the frequency falls just below nominal, i.e. 47Hz on

a 50Hz syatem or 57Hz on a 60 Hz system.

CONTROLCONTROLCONTROLCONTROL FUNCTIONFUNCTIONFUNCTIONFUNCTION DIRECTIONDIRECTIONDIRECTIONDIRECTION Volts To adjust generator output voltage Clockwise increase output voltage Stability To prevent voltage huntiong Clockwise increase the damping effect Stab switch To optimise transient performance Short the "B" and "D" terminal by Jumper cable UFRO To set the UFRO knee point Clockwise increase the knee point frequency

AVR CONTROLSAVR CONTROLSAVR CONTROLSAVR CONTROLS

Frequency Selection

UFRO

Stability

Slection

Indicator

B

DC

DREB

F2 F1

F2 F1 7 8

Volts

Stability

Connections

for the EBS

SHT25D-Y

2-5. CHANGE OF FREQUENCY

Engine

1. Change the lever① to required frequency position.

2. Loosen the adjusting bolt③.

3. Adjust the engine revolution to the set up rpm

by the adjusting bolt②. (See the below chart.)

4. After that, hold the adjusting bolt position

by the fixing nut③.

AVR

1. Change the jumper link to required frequency position.

(Reffer to page 12)

Others

1. Change the circuit protector to suitable capacity one.

(Reffer to page 7)

50 Hz 60 Hz

52 ~ 53 Hz 62 ~ 63 Hz

- 13 -- 13 -- 13 -- 13 -

Type

Set up rpm

(no load)

Change

lever

(engine)

Frequency

selection

(AVR)

①①①① ②②②②

③③③③

50Hz60Hz

3. TROUBLESHOOTING SHT25D-Y

3-1. GENERATOR

NOTE : In order to replace the parts in safety, remove negative terminal of battery so as to prevent the battery

and the parts from short-circuiting.

3-1-1. Evident Physical Dedects (Overheating, Noise, Vibrations…)

Excessive overheating of

bearing (With or without

abnormal bearing noise)

Disassemble bearing

* If the has turned blue or if the grease has

turned black, change the bearing.

* Bearing race badly locked (moving in its

housing)

* Bracket misalig

Excessive overheating of

alternator frame

Check

* Air inlets and outlets of

alternator

* Measureing equipment

(Voltmeter-Ammeter)

* Air flow (inlet-outlet) partially clogged or hot

air is being recycled either from alternator or

prime mover.

* Alternatoe over loaded.

Stop the gen-set and check the

installation.

* Three phase alternator is single phase

loaded in excess of acceptable lebel.

Start up with no-load :

if humming persists…* Short-circuit in the alternator stator.

Alternator damaged by a

significant impact which is

followed by humming and

vibration

Stop the gen-set immediately.

* Short-circuit in external circuit.

* Break or deterioration in the coupling.

* Break or twist in shaft extention.

* Shifting or short-circuit or the main field

winding.

Smork, sparks, or flames

issuing from the alternatorStop the set immediately.

* Short-circuit in external circuit

(including wiring between alternator and

control panel).

* Object fallen into the machine.

- 14 -- 14 -- 14 -- 14 -

Fault Action Origin of fault

Excessive vibration and

humming noise coming

from the alternator.

SHT25D-Y

3-1-2. Voltage Faults

* The alternator builds up

and voltage is correct after

battery removal.

* Lack of residual magnetism.

* Check voltage between F1 and F2 of the AVR

(correct value 4～7 V).

* V < 3 V exciter faulty.

* The alternator builds up

but voltage does not reach

nominal value after battery

removal.

* Check the connection of the sensing leads to

the AVR.

* Readjust the trimmer (VOLTS) voltage.

* The alternator builds up

but voltage collapses after

battery removal.

* AVR failure

* Chech the connection of the sensing leads to

the AVR.

* Exiciter windings shorted or open circuit

(check winding).

Voltage too

high

Adjust trimmer

voltage

No adjustment of voltage,

measure voltage between

F1 and F2 on AVR

Voltage between F1 and F2 < 3 V

AVR faulty.

* Check speed for possible cycle irregularity.

* Check out put connections.

* Faulty AVR.

* Speed below nominal on load.

* A rotating diode is open circuit.

* Auxiliary winding is open circuit (check

resistance values).

Voltage between F1 and F2

is < 4 V (D.C.)* Check speed.

Voltage between F1 and F2

is < 3 V (D.C.)

* Fault in rotating diodes.

* Short circuit in main field, check resistance.

* Exciter rotor faulty (check values).

Voltage

collapses

during

normal

operation

Check the AVR, the

surge suppressor,

the rotating diodes

and replace any

defective part

* The output voltage does

not return the nominal

voltage

* Exciter winding faulty (check values).

* Main field faulty (check values).

* Faulty exciter rotor.

Voltage

correct on

no-load, too

low on load

Run on no-load and

check voltage

between F1 and F2

- 15 -- 15 -- 15 -- 15 -

ActionDefect Measure Origin of fault

No voltage at

no load or

start up

Connect a 12V

battery for two or

three seconds to

terminals F1 and F2

from the generator.

Voltage

oscillation

Adjust trimmer

stability* If no result

SHT25D-Y

3-1-3. Engine Circuit Troubleshooting

NO

YES

NO

YES NO

NO YES NO

YES

YES

NO

YES

NO

YES

- 16 -- 16 -- 16 -- 16 -

1) Engine stops.

Dose the engine stop

approximately 10 second

after starting ?

Stop at soonest

after startingIs the engine oil

at the specified level ?

Dose monitor shows

overheating ?

Is the cooling water

at the specified level ?Is the cooling water

at the specified level ?

# Insufficient

engine oil # Insufficient

cooling water

# Difective oil pressure

sensor

# Defective water

water temperature

# Defective wiring

# Insufficient

cooling water

# Clogged radiator

# Engine breakdown

# Insufficient fuel

# Insufficient engine oil

2) Charg fault lamp does'nt light when key

switch is turned on and engine is not running.

Dose the charge fault lamp

operate normally ?

Is the 10 A fuse intact ?

# Broken lead to

charge fault lamp

# Broken wiring

# Short-circuited wiring # Burnt out 10 A fuse

Engine Circuit Troubleshooting

Sequence Chart

SHT25D-Y

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

- 17 -- 17 -- 17 -- 17 -

3) Charg fault lamp does not go off when engine is running.

Is the fan velt normal ?

Is the wiring normal ?

# Broken lead to

charge fault lamp # Defective alternator

# Brokenwiring

# Short-circuited wiring

4) Engine does not stop when key switch is OFF position.

Is the wiring normal ?

Dose the stop solenoid

operate normally ?

# Broken lead to

charge fault lamp

# Defective engine

# Defective

emergency relay

# Defective

stop solenoid

Is the 15 A fuse intact ?

# Burnt out fuse

SHT25D-Y

Engine stops during operation.

Engine starts, but stops after about 10 sec.

(Checking method) Are the oil pressure and water temperature monitor lamp normal ?

Oil pressure monitor lamp shows abnormal.

(Checking method) Check the fuse for continuity with an ohmmeter.

Charge fault lamp does not light even

with the key switch turned to "ON"

when the engine is stopped.

Charge fault lamp is not off even

when the engine is running.

Engine does not stop even

after key switch to "OFF"

- 18 -- 18 -- 18 -- 18 -

# Insufficient engine oil Add more oil

# Oil pressure will not go up Check the

related point

Water temperature monitor lamp

shows abnormal. # Insufficient cooling water

Add more

cooling water

# Overheats when water

temperature rises

Check the

related points

# Fuse 10 A burned out Replace

# Charge fault lamp burned Replace

# Wiring disconnection or short-circuit Replace

# Alternator failure Replace

# Broken fan velt Replace

Replace

# Stop solenoid failure Replace

# Wiring disconnection or short-circuit Repair

# Fuse (15 A) disconnection Replace

# Wiring disconnection Replace

Oil pressure and water temperature

monitor lamps are normal. # Oil pressure sensor failure Replace

# Water temp. sensor failure Replace

# Wiring short-circuit Repair

# Emergency relay failure

a) Engine stops.

b) Engine stops.

Dose not pass current.

Engine Circuit

Trouble Diagnosis

SHT25D-Y

3-2. ENGINE

Engine Does Not ・ No fuel Replenish fuel

Start ・Air in the fuel system Vent air

・Water in the fuel system Change fuel and repair

or flush fuel system

・Fuel pipe clogged Clean

・Fuel filter clogged Replace

・Excessively high viscosity of fuel or engine Use the specified fuel

oil at low temperature or engine oil

・Fuel with low cetane number Use the specified fuel

・Fuel leak due to loose injection pipe Tighten nut

retaining nut

・Incorrect injection timing Adjust

・Fuel camshaft worn Replace

・Injection nozzle clogged Clean or replace

・Injection pump malfunctioning Repair or replace

・Seizure of crankshaft,camshaft,piston, Repair or replace

cylinder liner or bearing

・Compression leak from cylinder Replace head gasket,

tighten cylinder head screw,

glow plug and nozzle holder

・Improper valve seat alignment,valve Repair or replace

spring broken,valve seized

・Improper valve timing Correct or replace timing gear

・Piston ring and liner worn Replace

・Excessive valve clearance Adjust

Starter Does Not ・Battery discharged Charge

Run ・Starter malfunctioning Repair or replace

・Key switch malfunctioning Repair or replace

・Wiring disconnected Connect

Engine Revolution Is ・Fuel filter clogged or dirt Replace

Not Smoothly ・Air cleaner clogged Clean or replace

・Fuel leak due to loose injection pipe Tighten nut

retaining nut

・Injection pump malfunctioning Repair or replace

・Incorrect nozzle opening pressure Adjust

・Injection nozzle stuck or clogged Repair or replace

・Fuel over flow pipe clogged Clean

・Governor malfunctioning Repair

・Air in the fuel system Vent air

Either White or Blue ・Excessive engine oil Reduce to the specified level

Exhaust Gas Is ・Piston ring and liner worn or stuck Repair or replace

Observed ・Incorrect injection timing Adjust

・Deficient compression Check and repair

Symptom Probable Cause Solution

- 19 -- 19 -- 19 -- 19 -

SHT25D-Y

Either Black or Dark ・Overload Lessen the load

Gray Exhaust Gas Is ・Low grade fuel used Use the specified fuel

Observed ・Fuel filter clogged Replace

・Air cleaner clogged Clean or replace

Deficient Output ・Incorrect injection timing Adjust

・Engine's moving parts seem to be seizing Repair or replace

・Uneven fuel injection Repair or replace the

injection pump

・Deficient nozzle injection Repair or replace the nozzle

・Compression leak Replace head gasket,

tighten cylinder head

screw and nut,glow

plug and nozzle holder

・Air in the fuel system Vent air

Excessive Lubricant ・Piston ring's gap facing the same direction Shift ring gap direction

Oil Consumption ・Oil ring worn or stuck Replace

・Piston ring groove worn Replace the piston

・Valve stem and guide worn Replace

・Oil leaks from defective packing Replace or repair

Fuel Mixed into ・Injection pump's plunger worn Replace pump element

Lubricant Oil or pump

Water Mixed into ・Head gasket defective Replace

Lubricant Oil ・Crankcase or cylinder head flawed Replace

Low Oil Pressure ・Engine oil insufficient Replenish

・Oil strainer clogged Clean

・Oil filter cartridge clogged Replace

・Relief valve stuck with dirt Clean

・Relief valve spring weaken or broken Replace

・Excessive oil clearance of crankshaft bearing Replace

・Excessive oil clearance of crank pin bearing Replace

・Excessive oil clearance of rocker arm Replace

・Oil passage clogged Clean

・Different type of oil Use the specified type of oil

・Oil pump defective Repair or replace

High Oil Pressure ・Different type of oil Use the specified type of oil

・Relief valve defective Replace

- 20 -- 20 -- 20 -- 20 -

Symptom Probable Cause Solution

SHT25D-Y

Engine Overheated ・Engine oil insufficient Replenish

・Fan belt broken or tensioned improperly Replace or adjust

・Cooling water insufficient

・Radiator net and radiator fin clogged with dust Replenish

・Inside of radiator corroded Clean

・Cooling water flow route corroded Clean or replace

・Radiator cap defective Clean or replace

・Overload running Replace

・Head gasket defective Lessen the load

・Incorrect injection timing Replace

・Unsuitable fuel used Use the specified fuel

・Cooling air for unit insufficient Remove the obstacle

Battery Quickly ・Battery electrolyte insufficient Replenish distilled

Discharge water and charge

・Fan belt slips Adjust belt tension or replace

・Wiring disconnected Connect

・Alternator defective Replace

・Battery defective Replace

Symptom Probable Cause Solution

- 21 -- 21 -- 21 -- 21 -

4. DISASSEMBLY AND SERVICING SHT25D-Y

4-1. EXTERNAL COMPONENT

Cover, Battery, Draining

1. Place the generator on a firm and level surface.

2. Remove the maitenance cover① and side cover②.

3. Open the drain cock to drain cooling water.

4. Remove the drain plug and drain engine oil.

5. Remove the battery negative cable, and next ,

the plus cable.

6. Remove the fuel tank cap③.

7. Remove the upper cover④.

Fuel tank

8. Return the fuel tank cap to the fuel tank⑤.

9. Close the fuel filter cock.

10. Remove the exhaust pipe and air bleeding pipe

from the fuel filter⑥.

11. Remove the fuel filter.

12. Remove the battery cables from the fuel tank.

13. Remove the fixing bolt of the fuel tank.

14. Remove the fuel tank from maintenance cover side.

Front cover, Control panel

15. Remove the front maintenance cover⑦.

16. Remove the wiring of the lower part on the terminal⑧.

17. Remove the fixing bolt of the terminal.

18. Remove the AVR maintenance cover⑨.

18. Disconnect the connector between the alternator

and AVR.

19. Remove the fixing bolt of the front cover.

Rear cover

20. Remove the fixing bolt⑧ of the exhaust pipe.

21. Remove the upper radiator hose, and next,

lower radiator hose.

22. Remove the fan cover⑪.

22. Remove the fixing bolt of the rear cover.

Battery and battery tray

23. Remove the battery.

23. Remove the battery tray⑫.

- 22 -- 22 -- 22 -- 22 -

⑧⑧⑧⑧

⑤⑤⑤⑤

⑥⑥⑥⑥⑦⑦⑦⑦

⑩⑩⑩⑩

④④④④

①①①①

②②②② ③③③③

⑨⑨⑨⑨

⑪⑪⑪⑪ ⑫⑫⑫⑫

Rear coverRear coverRear coverRear coverFront coverFront coverFront coverFront cover

SHT25D-Y

4-2. GENERATOR

EBS unit

1. Remove the terminal box lid① and D.E. screen②.

2. Remove the nuts③ for generator side mount.

3. Loosen the nuts for engine side mount.

4. Remove the bolts④ for EBS unit⑤.

5. Remove the EBS unit, take care not to damage windings.

EBS rotor

6. Remove the bolts⑥ for EBS rotor⑦.

7. Remove the EBS rotor⑦.

Stater

8. Loosen the fixing bolts⑦ for the D.E. adaptor⑧ slightly.

9. Put a jack under the D.E. adaptor.

10. To avoid damage to the stator and rotor, suspend the

generator with a sling enough to keep it from lifting,

and leave it suspended.

11. Jack up the generator slowly to the position where the

mounting bolts becomes free.

12. To work safety, Remove the fixing bolts⑦.

13. Set a puller⑨ to the N.D.E. bracket, and pull up slowly

till a bearing deviates from bearing housing.

14. Remove a puller⑨.

15. Remove the stator assembly, take care not to damage

windings (main and exciter).

Rotor

16. To avoid damage to the rotor, suspend the rotor with a

sling enough to keep it from lifting, and leave it suspended.

17. Remove the fixing bolts⑩ for the disc coupling.

18. Remove the rotor assembly, take care not to damage winding.

- 23 -- 23 -- 23 -- 23 -

①①①①

②②②②③③③③

④④④④

⑤⑤⑤⑤

⑥⑥⑥⑥

⑦⑦⑦⑦

⑧⑧⑧⑧

JackJackJackJack

⑨⑨⑨⑨

⑩⑩⑩⑩

SHT25D-Y

4-3. SERVICING

(A) Terminal voltage for each part during No-load period

1. With the NFB in the "ON" position, measure the

voltage in each phase and each line.

2. If the factory spec. is not indicated, inspect the output

circuit or the wiring harness. (Refer to wiring diagram)

< SHT25D >

Line

Phase

(B) Stator coil

Main winding

1. Test for continuity between coil leads with a miliohm meter.

2. If the resistance is not as specified, replace the main stator.

# Measurment is not possible with a regular tester.

Excitor winding

1. Measure the coil resistance between each auxiliary winding

F1-F2.

2. If the resistance is not as specified, replace the excitor stator.

EBS unit winding

1. Measure the coil resistance between each winding.

2. If the resistance is not as specified, replace the main stator.

Grounding of Stator coil

1. Measure the insulation resistance between each stator

winding and lamination with a mega ohm meter.

2. Reading should be more than 1MΩ at DC 500V.

3. If continuous, after dry the stator with an appropriate way,

measure the insulation resistance again.

If continuous still, replace the main stator or contact service.

See page 7

ResistanceFactory

spec.

- 24 -- 24 -- 24 -- 24 -

ResistanceFactory

spec.See page 7

415 V +/- 10 V

240 V +/- 10 V

Factory

spec.

Output

voltage

F1-F2

each

windingSee page 7

ResistanceFactory

spec.

< SHT25D >

Miliohm meter

F1markF2mark

Main winding

Excitor

EBS unit winding

3P connector

Measurment Point

SHT25D-Y

(C) Rotor coil

Main rotor winding①①①① and Excitor rotor winding②②②②

1. Remove the field coil end at the rotating rectifire assembly.

2. Measure the coil resistance between each end of field coil.

3. If the resistance is not as specified, replace the rotor

assembly.

Main

Excitor

# Measurment is not possible with a regular tester.

Grounding of Rotor coil

1. Measure the insulation resistance between each rotor

winding and lamination with a mega ohm meter.

2. Reading should be more than 1MΩ at DC 500V.

3. If continuous, after dry the rotor with an appropriate way,

measure the insulation resistance again.

If continuous still, replace the main rotor or contact service.

(D) Initial excitation method

The generator is self exciting from the residual magnetism

of the magnetic circuit of the excitor. When first tested

(at the factory) this magnetic circuit is magnetized but

after a breakdown it may be necessary to remagnetize.

1. 12V battery is used for initial excitation.

2. Stop the generator and disconnect the AVR cable.

3. Connect the battery's positive and negative cables

to the generator's F1 and F2 terminal, respectively,

for just 2 or 3 seconds.

4. Connect and run the generator.

# If the connection has the wrong polarity or different

position (such as F1 and F2 side) magnetization is

reversely reduced.

See page 7

- 25 -- 25 -- 25 -- 25 -

ResistanceFactory

spec.

①①①①②②②②

(Excitor winding)

Mega ohm meter

Miliohm meter

SHT25D-Y

(E) Control panel

AC ammeter <SH25D only>

1. Test for continuity between the ammeter terminals

with an ohmmeter.

2. Replace the ammeter if there is no continuity.

Circuit breaker

1. Test for continuity between the each upper and lower

breaker terminals with an ohmmeter.

2. Confirm that there is continuity when the breaker switch

in "ON".

3. If there is no continuity, it indicates that the contacts

are faulty. Replace the breaker.

Current Transformer (CT for Ammeter) <SH25D only>

1. Disconnect the lead wire from one side of the CT.

2. Test for continuity between the CT terminals

with an ohmmeter.

3. Replace the CT if there is no continuity.

Lamp timer (for Glow plug)

1. Remove the lamp timer from inside of the panel.

2. Connect the 12V battery①, lamp timer② and bulb③

as shown in the figure.

3. The bulb③ light up when contacting the lead wire④

with positive terminal of the battery① and goes off

approximately 5 seconds late, the lamp relay is proper.

- 26 -- 26 -- 26 -- 26 -

①①①①

②②②②

③③③③

④④④④

SHT25D-Y

Oil pressure sensor

1. The normal oil pressure sensor has continuity when

the engine is stopped and has no continuity while the

engine is running.

2. Replace the sensor if it is defective.

Water temperature sensor

1. Insert the water temperature sensor in the engine oil,

and continue the circuit when the oil temperature rises

above than 115 +/- 3℃.

2. Check that the resistance is 0 ohm in case sensor

is defective.

Emergency relay circuit

1. When the engine is running at rated rpm, connect the

lead wires to the terminal of the oil pressure sensor or

the water temperature sensor.

2. Aiso ground the other end of the lead wires to an

unpainted portion of the engine frame.

(In normal operation)

・ The stop solenoid activates and the engine stopes

automatically.

・ As the stop solenoid is acivated again after 10 +/- 3 sec

of its first engagement, a 'tick' sound can be heard.

- 27 -- 27 -- 27 -- 27 -