Motor starters and contactors are motor-starting devices. They combine a contactor with overload protection and are designed for starting AC or DC motors. Motor starter ratings include continuous current, thermal current, motor voltage, and power. Continuous current, a specification which is also known as continuous ampere rating, measures the ability of motor starters and contactors to handle current over a continuous period. Thermal current is directly proportional to the coefficient of...
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Q & A on Motor Starters and Contactors
We asked our users for their input on Motor Starters and Contactors. Here are the results of 82 users familiar with Motor Starters and Contactors.
Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying AdviceDesign TrendsTop
What new technologies are influencing motor starter and contactor design?
13 answers
Lamination design is such that commutator is pressed inside after winding, hot stacking & machining to reduce the length of shaft & envelope. size
~Manufacturing, Mohali, India
Low oil consumption, modular system of auxiliary block contacts, modularity of overload protection, electrical durability...
~Ilija S, Marketing/Sales, Skopje, Macedonia
Capabilities of building smaller size starters
Tool less, plug connection design
Communication-capable starter components
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~Ernest G., Construction Engineer, Espanola, NM
From your perspective, which companies are creating the most innovative motor starters and contactors?
15 answers
Siemens, ABB, Schneider Electric, but there are many private companies specializing in assembly of MCC's using high quality modular enclosures Form B etc fitted out with end user preferred components as mix and match, which helps the end user in standardization of spare parts.
~Keith T, Project Manager, Dubai, UAE
Rade Koncar-Kontactori i relei, Skopje, Macedonia, Schneider, Siemens, ABB,..
~Ilija S, Marketing/Sales, Skopje, Macedonia
Siemens, ABB are good manufacturers.
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~Maintenance/Facilities Management, North killingholme, Great Britain
Applications and UseTop
What are some of the applications you have used motor starters and contactors for?
21 answers
Conveyors, Bucket Elevators, Furnace Cooling Fans, Pumps, Motor Operated Valves, Overhead Cranes, Cooling Water & Circulation Systems.
~Keith T, Project Manager, Dubai, UAE
Vacuum contactors to start 6.6kV motors
DOL 415v ac motor starters
Contactors for crane applications
VSD motor controllers
~Maintenance/Facilities Management, North killingholme, Great Britain
VFD for well motors,HVAC motors, Compressor motors, Pump motors, and other equipment throughout the facility.
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~Larry F., Facilities Manager, Columbia, MO
Please share with us any “non-standard” applications that motor starters and contactors have been used for.
8 answers
The basic function of Motor Starters & Contactors is to switch power on and off to circuits. This is often done remotely and under automatic sequence control. The diversity of applications is limited only by the Designers imagination or the process needs. Its difficult to imagine anything Standard.
~Keith T, Project Manager, Dubai, UAE
When I was working for a Iron Plant in Venezuela, all MV motor starter were supported with Circuit Breakers, "the savings" by not purchasing & stock of MV limiter fuses during start-up and five year of operations, was amazing!!!
~Ysmael S, Principal Electrical Engineer, Bakersfield, CA
Switching DC for DC injection motor stopping devices. Switching high heating loads controlled by Electronic Controllers and SSR's - Eurotherm, Watlow controllers.
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~Peter W, Design Engineer, WATFORD Herts, United Kingdom
Do you know of any disastrous mistakes that occurred due to the incorrect usage of motor starters and contactors?
3 answers
Yes, frequent failure including the welding of contacts on the contactors due to high fault currents occurring when SSR's fail.
~Peter W, Design Engineer, WATFORD Herts, United Kingdom
Not at this point in time.
~Anthony M, General Management, Mentone, IN
None to my knowledge.
~Keith T, Project Manager, Dubai, UAE
FeaturesTop
What would your design or feature "wish list" be for this product?
9 answers
There are so many designs and applications to prepare a simple wish list of preferred manufacturers for components. The important thing is simplicity of design, easy access for maintenance and good quality.
~Keith T, Project Manager, Dubai, UAE
Compact, may be mounted horizontally or vertically, able to withstand higher prospective fault currents say 10kA up to 30kW and 20kA up to 100 kW
~Peter W, Design Engineer, WATFORD Herts, United Kingdom
Ruggedness for frequent start stop applications with up to 300 start stops in 16 hours, IDC in Light commercial vehicles, brushless
~Manufacturer, Mohali, India
1. Very High Reliability ( implicit very low shutdown for maintenance )
2. Low volume and low weight
3. Competitive Cost
~Ysmael S, Principal Electrical Engineer, Bakersfield, CA
In progress, cost effective & control losses after 30,000 cycles
~Manufacturing, Mohali, India
Universal mounting scheme
Full range adjustable overloads
~Ernest G., Construction Engineer, Espanola, NM
Easier to trouble shoot for some of my helpers.
~Larry F., Facilities Manager, Columbia, MO
I can not discuss that at this point in time.
~Anthony M, General Management, Mentone, IN
POWER ELECTRONIC STARTERS,MAGNETIC STARTERS
~Engineering, Faculty/Staff/Student, Yanbu, Saudi Arabia
Is there any advice you want to share with users to help them avoid common errors in selection or usage of motor starters and contactors?
7 answers
Common error is cost cutting by elimination of visual indication. Motor managers log the circuit running data, but local visual indication is often eliminated. Running and stopped (ON/OFF) indication lamps give at a glance confirmation that all is well. LED panel indication lamps are inexpensive and virtually maintenance free.
~Keith T, Project Manager, Dubai, UAE
One frequent mistake found in field testing is that many electrical designers are using limiting fuse and contactor in large MV motors ( 1500 HP and more), this scheme is not suitable for differential protection but include as protective elements Multilin 469 or equivalent with 87M prot function on disable setting.
~Ysmael S, Principal Electrical Engineer, Bakersfield, CA
Try and obtain actual prospective fault currents at site of use, as these days with larger and larger supply transformers in use on large sites, these may be higher than expected.
~Peter W, Design Engineer, WATFORD Herts, United Kingdom
Siemens type 2 Co-ordination for D.O.L starting is wrong on the 7.5kW starter it should be 32A fuse not 25A.
~Design Engineer, Bristol, Great Britain
Keep coil voltages constant throughout your facility for ease of maintenance.
~Ernest G., Construction Engineer, Espanola, NM
Rebuilt ones will wear out quickly.
~Anthony M, General Management, Mentone, IN
Make sure about selection.
~Ahmed Sebaa, Electrical supv., Yanbu, Saudi
Buying AdviceTop
Do you have any advice for people relative to buying or using motor starters and contactors?
6 answers
If you are using them for anything other than "run of the mill starters" look carefully at the operating parameters and make sure your selection will meet those parameters.
~Peter W, Design Engineer, WATFORD Herts, United Kingdom
Keep the design simple, modular and interchangeable. Always provide good access for maintenance.
~Keith T, Project Manager, Dubai, UAE
Besides sizing the starter and overloads, use the correct type of enclosure for the application.
~Ernest G., Construction Engineer, Espanola, NM
Buy or use the best quality.
~Anthony M, General Management, Mentone, IN
Use the the right size.
~Ahmed Sebaa, Electrical supv., Yanbu, Saudi
Not right now
~Ysmael S, Principal Electrical Engineer, Bakersfield, CA
