type of motor and starter?
type of motor and starter?
(OP)
I need some information on type of starter and rating(kW or hp) for each starter. Is there any book i can refer too or website said about type of starter used for how many kW. Is there any regulation for it?Eg : DOL can be used for <5kW motor. A/T for > 15kW.





RE: type of motor and starter?
the problem is not that simple. It really depends on 2 main things: application and bus strength.
1. Application. You may need a VSD on a small potable water pump that has a 1.5 kW motor, and you may want to DOL a 250 kW exhaust fan or a 400 kW fire pump. The application is an important consideration.
2. Bus strength. You need to model what is happening to the bus voltage during starting. For instance, you can easily DOL a 400 kW motor as long as you have a nice strong system ahead of it. The MVA during starting DOL must be worked out and compared to bus MVA (short circuit fault available) and other running loads need to be considered.
HTH
RE: type of motor and starter?
Hope this helps
WWW.AB.COM
RE: type of motor and starter?
http://ecatalog.squared.com/techlib/
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Technical Library
Motor Control
RE: type of motor and starter?
My problem, I was given 2 tables from 2 different sources for starting method.Both sources are different in rating power for equipments. Source A used <2.238kW for DOL, while source B used <5kW for DOL. Source A used 2.238-7.46 kW for Starr Delta/Auto trans ,while 5-15kW for Star-Delta. For the rest ,source A used Rotor Resistance and source B used Auto trans.
Therefore, I need clarification on both rating,which one to follow.
Thank you
RE: type of motor and starter?
-The motor will deliver the power required by the application
- The starting characteristisc depends on the load, motor inherent characteristic, and the type of starter.
- The bus strength decides the capacity of the power that can be delivered especially during starting.
RE: type of motor and starter?
The science of motor starting includiong motor selection, and starter selection is not well understood or engineered in most situations that I have come across. You are correct in asking these questions.
Firstly, you need to consider the driven load. The driven load has a minimum torque requirement in order to accelerate to full speed in a reasonable time. This determines your minimum starting torque.
Secondly, the motor acts as a transducer to convert amps into newton meters (torque) and this determines the minimum starting current to achieve the torque required by the load. Please note that motors vary dramatically in their ability to convert current into torque during start!!
Thirdly, the starter can control the current/voltage applied to the motor to limit the starting current to that required by the motor to start the load.
Finally, the supply dertermines the maximum starting current that can be delivered to the motor.
If you follow the sequence above and optimise each component, load, motor, starter and supply, you will get the best results.
In many situations, reliance is made that the starter will eventually end up on full voltage and the motor will start the load at that time. In these cases a simple DOL starter would be cheaper and more effective.
If you look at my site, http://www.lmphotonics.com you will find more information on the science of motor starting.
Best regards,
Mark Empson
http://www.lmphotonics.com
RE: type of motor and starter?
My problem, I was given 2 tables from 2 different sources for starting method.Both sources are different in rating power for equipments. Source A used <2.238kW for DOL, while source B used <5kW for DOL. Source A used 2.238-7.46 kW for Starr Delta/Auto trans ,while 5-15kW for Star-Delta.
///The source B is providing a larger kW margin. Nature of motor load and motor duty cycles may have influenced that.\\\
For the rest ,source A used Rotor Resistance and source B used Auto trans.
///Resistors tend to be more often used. The autotransformers tend to provide smoother start with less energy waste.\\\
Therefore, I need clarification on both rating,which one to follow.
///The proper recommendation will require additional information, e.g.
1. Describe the motor load nature
2. Describe the motor duty
3. What is the motor rated voltage?
4. Etc.\\\