locked-rotor indicating code letter
- Thread starter sahafi
- Start date
- Status
bphgravity
Senior Member
- Location
- Florida
Re: locked-rotor indicating code letter
Locked-Rotor Current of a motor is the current taken directly by the motor at startup when the revolving part is held stationary verses a motor that is free to spin.
Table 430.7(B) of the 2002 NEC specifies the indicating letters of motors with locked rotor current. The letter indicates a certain design specification of the particular motor and its resistance characteristics.
Locked-Rotor Current of a motor is the current taken directly by the motor at startup when the revolving part is held stationary verses a motor that is free to spin.
Table 430.7(B) of the 2002 NEC specifies the indicating letters of motors with locked rotor current. The letter indicates a certain design specification of the particular motor and its resistance characteristics.
stew
Senior Member
- Location
- federal way,washington
Re: locked-rotor indicating code letter
bryan I would like to sort of split a hair here on this. The locked rotor letter indicates the locked rotor kva per hp wheras the design letter indictes the torque cpability of the motor. A normal torque motor is design B which a standard off the shelf motor. design D is hi torque and design e is hi torq hi slip with the slip being 5-8% or 8-13& slip depending on the exact application. The only reason I bring this up is to differentiate between the design letter the KVA code letter ant the term design. They all refer to the overall design of the motor but the design letter is a specific letter assigned to the torque charictaristics only as part of the overall design.
bryan I would like to sort of split a hair here on this. The locked rotor letter indicates the locked rotor kva per hp wheras the design letter indictes the torque cpability of the motor. A normal torque motor is design B which a standard off the shelf motor. design D is hi torque and design e is hi torq hi slip with the slip being 5-8% or 8-13& slip depending on the exact application. The only reason I bring this up is to differentiate between the design letter the KVA code letter ant the term design. They all refer to the overall design of the motor but the design letter is a specific letter assigned to the torque charictaristics only as part of the overall design.
Re: locked-rotor indicating code letter
Stew,for the USA, NEMA standard MG1 gives the requirements for motors and generators. MG1 Part 10.37 gives the locked rotor kva code leters and part 12 gives the torque and slip for the Design letters. USA manufacturers use the NEMA standard for the motor nameplate data. A lot of the rest of the world uses IEC standards and they usually use KW instead of horsepower. A one horse motor would be 0.75 KW.
Stew,for the USA, NEMA standard MG1 gives the requirements for motors and generators. MG1 Part 10.37 gives the locked rotor kva code leters and part 12 gives the torque and slip for the Design letters. USA manufacturers use the NEMA standard for the motor nameplate data. A lot of the rest of the world uses IEC standards and they usually use KW instead of horsepower. A one horse motor would be 0.75 KW.
stew
Senior Member
- Location
- federal way,washington
Re: locked-rotor indicating code letter
I believe I said the same thing you did gpedens. I am very familiar with MG1 I owned an electric motor shop fot 17 years where we had a rewind cpability of 500 hp andd sold motors up to 1500. Anyhow I was teethed on electric motors before I became an electrician.
I believe I said the same thing you did gpedens. I am very familiar with MG1 I owned an electric motor shop fot 17 years where we had a rewind cpability of 500 hp andd sold motors up to 1500. Anyhow I was teethed on electric motors before I became an electrician.
- Status