Solid State AC Motor Controls and Motor Protection Products · production, they increase the motor...
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Solid State AC Motor Controls and Motor Protection Products
Transcript of Solid State AC Motor Controls and Motor Protection Products · production, they increase the motor...
Solid State AC Motor Controls and Motor Protection Products
How resilience can be improved
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Our heritage
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Remember what happened in 1982…
Fairford Electronics Ltd
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35 years pioneering soft startertechnology & development
experts supporting step change advances in motor starting design
leaders in pushing
technology boundaries
new product development
DNA at our core
punching above our weight
as true industry innovators
pedigree and legacy
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digital microprocessor soft starter
automatic energy optimisation - iERS
voltage & current edge firing techniques
event logging software programme - StarterView
formulated algorithm for efficient 4SCR control – 3S Technology
on-line product selector
application pre-sets
automatic set-up
integrated touch screens
multiply controlled & coupled soft starters – PLUSS
re-rating software
industry 4.0 ready
pedigree and legacy – 1st mover status
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blue chip lineage
As the global technology leader for soft starters we have, and still do work in
partnership with leading organisations:
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market landscape by industry sector
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Centrifugal Pump Applications adhere to the cube law
By reducing the speed by a certain percentage, the power reduces by the cube of the speed change
Operating at 80% speed results in (0.8)³ = 51.2%
Therefore if we reduce the percentage Flow or Speed by 20% we can save 48.8% Power
Reliability of Assets – Selecting the correct product for the job
Variable Speed Drives
Affinity Laws - Energy Saving
/ Speed
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How good is this, why would we not use VSD’s on every motor application
Hold this thought
Motor Rating (kW) 90 Fixed speed cost £36,504
Daily use (hours) 12 Speed reduction (%) 20
Weekly use (days) 5 Power saving (%) 48.8%
Annual use (weeks) 52
kWh Cost (£) £0.13
Annual running cost £36,504 Annual energy saving £17,814
Reliability of Assets – Selecting the correct product for the job
Variable Speed Drives
Affinity Laws - Energy Saving
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The Affinity Laws govern the performance of the pump, predict pump performance at different velocities and should be used in the design of pumping systems
Typically pumps are directly coupled to the motor and the motor speed is the pump speed
Centrifugal pumps work with centrifugal force, the velocity and diameter of the impeller determine the head or pressure the pump can develop
The formula for the motor speed is:
Synchronous Speed n = 120 x frequency / poles
Standard electric motor speeds:
50Hz 60Hz2 pole motor 3,000 rpm 3,600 rpm4 pole motor 1,500 rpm 1,800 rpm6 pole motor 1,000 rpm 1,200 rpm8 pole motor 750 rpm 900 rpm
Reliability of Assets – Selecting the correct product for the job
Variable Speed Drives - Affinity Laws
Design in Pumping Systems
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The speed can be adjusted by multiples just by changing to a motor with a
different number of poles
All motors are designed with slip to ensure the starting torque and the running
torque
A low slip motor is better for pumping a liquid that flows like water (low
viscosity)
A high slip motor is better for pumping a liquid that flows like high dense oil
(high viscosity)
Reliability of Assets – Selecting the correct product for the job
Variable Speed Drives - Affinity Laws
Design in Pumping Systems
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The change in speed brings about a corresponding change in the head/pressure, flow, and
power requirements of the pump according to the Affinity Laws.
Law 1: Impeller diameter held constant
Flow is proportional to shaft speed
Pressure or Head is proportional to the square of shaft speed
Power is proportional to the cube of shaft speed
Reliability of Assets – Selecting the correct product for the job
Variable Speed Drives - Affinity Laws
Design in Pumping Systems
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The change in impeller diameter brings about a corresponding change in the head, flow, and
power requirements of the pump according to the Affinity Laws
Law 2: Shaft speed held constant
Flow is proportional to the impeller diameter
Pressure or Head is proportional to the square of the impeller diameter
Power is proportional to the cube of impeller diameter
Reliability of Assets – Selecting the correct product for the job
Variable Speed Drives - Affinity Laws
Design in Pumping Systems
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Why are these laws important with working with pumps. System designers equipment
operators like variable-speed motors for the first Affinity Law. If they need 20% more
production, they increase the motor speed by 20% and they get the production
increase
The head generated varies by the square of the velocity or impeller diameter change.
For example, increasing the pump speed by 20% would increase the head (pressure)
by close to 50 percent. This could burst the screens in a downstream filter or
overload a mechanical seal or even worst case cause damage to the piping system
A pump’s performance is composed of both the flow element and a head (pressure)
element. This is the reason VSDs seem to work well on fans and blowers, but not
necessarily on all pumps. You see, a fan or blower is only a flow application; if you
needed air pressure, you’d use a compressor, not a fan
Design Stages: Correct Selection – Why Complicate the design
Variable Speed Drives - Affinity Laws
Design in Pumping Systems
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The pump performance curve changes at different motor speeds. The profile of the
curve and its elements head, flow, power, NPSHR (net positive suction head
required), efficiency do not change. What changes are the units of flow and head on
the horizontal and vertical arms of the graph. They change by the Affinity Laws
Design Stages: Correct Selection – Why Complicate the design
Variable Speed Drives - Affinity Laws
Design in Pumping Systems
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The water industry is the biggest market sector for drives and Soft Starters mainly
used for freshwater and wastewater in order to provide communities with services
we all take for granted
Pumping systems are obviously used in other sectors such as in the chemical
sector, etc
Circulating water is used in warm countries for cooling and in colder countries for
heating
These systems differ in many ways, but there are two main types of pumping
systems – Pressurised Systems and Non-Pressurised Systems
Design Stages: Correct Selection - Why Complicate the design
Design in Pumping Systems – Different Pump Systems
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Pressurised Systems:
Traditionally from Water Towers
Feeder Pumps to regulate the pressure
Booster Pumps to increase pressure for longer distances
Non-Pressurised Systems
Typically for moving Waste Water horizontally or to elevate
Water flowing by gravity and collected in different reservoirs
Transferring water between different reservoirs or to the ocean
Design Stages: Correct Selection – Why Complicate the design
Design in Pumping Systems – Different Pump Systems
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Using Soft Starters in conjunction with a VSD will provide a more compact and cost
efficient solution than only using drives
Design Stages: Correct Selection – Why Complicate the design
Variable Speed Drives - Affinity Laws
Design in Pumping Systems – Pressurised Systems
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Another common problem in wastewater systems is clogging, which is caused by
having too slow speed of the water. This problem will be avoided by using constant
speed motors, controlled by Soft Starters
Design Stages: Correct Selection – Why Complicate the design
Variable Speed Drives - Affinity Laws
Design in Pumping Systems – Non-Pressurised Systems
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Typically the consumed power will be about 80% of the motor kilowatt rating. The annual running cost will actually be less and hence the annual energy saving less
However this example does not take into account the efficiency of the motor and the losses in the motor, typically an IE3 motor at 90kW will have an efficiency of 95% at 50%, 75% and 100% loading. The annual running cost therefore is more
This example forgets to account for the losses in the drive, typically in the region of 3% to 5% which again will make the annual saving less
Many applications the drive will be running at only fixed speed therefore due to the losses in the drive at 72kW more energy will be used the overall efficiency of the system now reducing from 95% efficient to 90.7% efficient
Reliability & Delivering Resilience – Problems of Drive Losses at fixed speed
Variable Speed Drives – The True Costs
Affinity Laws - Energy Saving
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Reliability & Delivering Resilience – Ease of Set Up & Implementation
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
Cost of Commissioning and level of competence to run both product systems:Typically VSD’s are much more difficult to use and set up and do require a high level of understanding
Soft Starters can provide:
Application pre-sets, automatic set-up and automatic features
Pre-programmed application 'complete setup' profiles with no further adjustments in less than a minute
Variable Speed Drives:
These can take in the region of over 2 to 3 hours per unit especially if there are PID loops to set up
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Time and time again VSD’s are used on fixed speed applications and we have already seen the actual running costs however there are further costs let us break them down:
Upfront Purchase PriceVSD’s in the region of at least 3 to 5 times the cost of Soft Starters up to about 110kW and up to about 10 times the cost of Soft Starters higher than this.
Dual rating for a constant torque load, frame size has to increased one frame size up
Panel Costs:Typical panel design to pumping station standards:
VSD’s in the region of 2 to 3 times the cost of Fixed Speed Drive Panel Costs
Panel Size:Because of the extra cooling requirements and the larger size of Variable Speed Drives cabinet sizing is far greater
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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Running Costs and Total Expenditure (TOTEX):
If the VSD is being used to run at fixed speed the operating losses of the drive per
year can be far greater than the first off initial costs of the Soft Starter
Also there are extra costs involved with cabinet cooling for the VSD’s. Some of the
larger units require their own dedicated compressor cooling system, some are also
water cooled
The majority of applications are fixed speed where varying load levels are
automatically balanced by the motor torque and there is not a requirement for VSD’s
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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Maintenance (refurb/replace) Cost:
Soft Starters it more a visual check
VSD’s a high level of maintenance, larger units require a yearly maintenance check, £1,500 per visit
Filter capacitors, pumps, batteries and fans require replacing.Water cooled units require their pressure checked annually as an example
Weaknesses with VSD’s, OEM’s &/or suppliers often means that preventative maintenance service plans are sold alongside the units as some components need regular replacement.
SOFT STARTERS DO NOT REQUIRE SERVICE PLANS
Use of low maintenance Soft Starter technology de-risks and improves profitability of servicing contracts 15-20 years in use
OEM’s in the compressor market are aware that leading brands of VSD’s typically have an average operational life of less than 10 years, making them costly to use on service plans longer than 5 years
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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Forced Ventilation Fan for the Motor Set:
To protect against motor heating it is recommended:
Forced ventilation fans at separate constant speed fan to increase cooling capacity & load capacity at low speeds
Directly measuring the motor’s surface temperature & using the data to control the shutdown of that motor
Monitoring and controlling the power fed to the motor
Limiting the load on the motor to prevent loads that cause higher motor heating
The cost of a forced ventilation fan can be nearly the cost of the motor itself
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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Chokes & filters
Variable Speed Drives Require:
du/dt filters - Differential-mode filters which reduce motor terminal phase-to-phase peak voltage spikes and reduce the rise time lowering the stress on the insulation of motor windings
dv/dt filter reactors are a vital system component that allow longer cable runs and suppress the harmonics at the higher frequencies
RFI filtering and chokes for reducing high frequency disturbances via conductive emissions
LCL filter in the case of regenerative drives
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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Protecting against bearing current:
VSD’s can cause common mode voltages which induces voltages across motor bearings, leading to current flow through motor bearings the motors have to be fitted with insulated non-drive end bearings in order to break circulating current paths and larger frame sizes has to have a common mode filter installed
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
Blocking Resistor:
This helps blocks the regenerative power flowing back on the line that can cause overvoltage trips
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Shielded Screen Cables for EMC Compatibility:
Enclosure, cabling and wiring should conform and employ measures to form Faraday cage against radiated emissions in the form control and power cabling. The installation includes cabinets, auxiliary boxes, cabling, motors, etc.
Consideration of panel layout in separation and partition, positioning of filters and power of the incoming supply in the panel design, special shielded cables entries
Encoders:Converting the angular position or motion of a shaft or axle to an analogue or digital signal for feedback
Motor Protective Circuit Breakers:To ensure they can accommodate working with Variable Speed Drives and have the correct isolating characteristics
Reliability & Delivering Resilience
Soft Starters & Variable Speed Drives – TOTEX – Total Expenditure
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StarterView captures and records multiple application events and with full data
analysis available through Fairford’s ‘StarterView’ programme we provide
operators with the necessary and critical data required when undertaking
active predictive maintenance strategies.
• Life Event Logging
– fast and accurate fault analysis and their resolution
– life &/or last 1,600 application events recorded
– recording multiple activities:
start, stop, top of ramp, faults, application parameters – time,
overload, currents and frequency
– equipment &/or component failure predictions during planned maintenance
– avoids unwanted breakdowns
– optimised performance and equipment conditioning
– reduced lost production time
– lower operation & maintenance costs
intelligent capability - StarterView
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monitoring & event logging
Log File with StarterView
• Records every event
– Trips, Current’s, Overload Level, Heatsink Temperature, Frequency, Energy Saving parameters, Plus others
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monitoring & event logging
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Parameters
• Configuration (Parameters) Upload/Download
• Configuration Backup and Maintenance
• Side by side comparison of Parameter files
• Modbus PNU information
Log file
• Detailed Analysis of application parameters
• Fast system fault finding, not just the soft starter
• Ability to trend popular parameters
• Produce a graph of popular parameters
• Predictive maintenance
Email and print configuration & log files
Firmware upgrade wizard
Available on-line: www.fairford.com/support/starterview
performance analysis
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Motor Control – The advantages and disadvantages of using Variable Speed Drives
and Fixed Speed Drives (Soft Starters) in the Water Sector applications we must first
understand the system and its overall design
Reliability of assets should be analysed through the selection of the correct product,
not over complicating system design, reliability and delivering resilience through ease
of set up, TOTEX costs, panel costs and predictive maintenance strategies ensuring
an informed decision as to which piece of equipment should be incorporated into the design.
Leading control gear specialists, distributors, system integrators, OEM’s and end
users have all seen the benefits of using VSD’s and Soft Starters together. Using the
benefits of both systems in a package will provide Resilience and the most efficient solution and the most viable cost effective package
Starting, Stopping & Running Pumps in the Water Sector
How resilience can be improved
thank
you
