motor question
- Thread starter normbac
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RMD1994
Member
- Location
- Denver, CO
The 220/380/440 nameplate refers to the different voltages that the motor will run on. By changing wire connections in the motor you can utilize any of these 3 voltages you may have at your location. You have a 277/480 and a 120/208 panel available, so you will be able to connect to 208 or 480 depending on how you have yor motor wired.
my concern was whether the 208 would be enough voltage wasnt sure if 208 would be enough voltage for a motor rated 220
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
The 220/380V rating indicates it's an IEC design motor. The way to tell is to look at the connection diagram. If it indicates that you need to connect the motor in Wye (Star) for the higher voltages and Delta for the 220V, then it's an IEC design. The problem is, they tend to have less tolerance to adverse conditions than NEMA design motors do. Typical NEMA designs have a "Service Factor" that accounts for voltage variations of + or - 10%. The SF then allows for full loading at the extremes of the tolerance without concern for over stressing the motor. IEC designs usually have the same +-10% tolerance, but there is NO Service Factor, they are essentially the same as a 1.0SF rated motor.
On top of that, the motor rating would be based on 220V or 380V 50Hz, or 440V 60Hz. What this means is that the design of the motor is base on putting out full torque at 220V 50Hz, based upon a V/Hz ratio of 4.4:1 To maintain the same V/Hz ratio at 60Hz, the voltage would need to be 264V. Without it, you will be under fluxing the motor and it will produce less torque; about 30% less than rated. So if your application is lightly loading that motor, you can probably go that route. But if it's running right up against the nameplate FLA, I would go with the higher voltage.
But...
The "440V" rating is again base on the 380V/50Hz ratio of 7.6:1, so if you increase the voltage to 440V/60Hz, you are really close (460V would be better). Using a voltage that is significantly higher than the design ratio permits will mean you are over fluxing the windings, causing the excess to become heating without producing more work. That still may be preferable however, especially if the load is asking a lot of that motor. So if you can use a 480V input, I would go that way. The motor will run a bit warm, but you will be able to get full loading from it.
On top of that, the motor rating would be based on 220V or 380V 50Hz, or 440V 60Hz. What this means is that the design of the motor is base on putting out full torque at 220V 50Hz, based upon a V/Hz ratio of 4.4:1 To maintain the same V/Hz ratio at 60Hz, the voltage would need to be 264V. Without it, you will be under fluxing the motor and it will produce less torque; about 30% less than rated. So if your application is lightly loading that motor, you can probably go that route. But if it's running right up against the nameplate FLA, I would go with the higher voltage.
But...
The "440V" rating is again base on the 380V/50Hz ratio of 7.6:1, so if you increase the voltage to 440V/60Hz, you are really close (460V would be better). Using a voltage that is significantly higher than the design ratio permits will mean you are over fluxing the windings, causing the excess to become heating without producing more work. That still may be preferable however, especially if the load is asking a lot of that motor. So if you can use a 480V input, I would go that way. The motor will run a bit warm, but you will be able to get full loading from it.
Last edited:
If it is an IEC 50Hz design, it isn't just the voltage you need to consider.
On 60Hz, it will run 20% faster. That may be OK for the motor but maybe not OK for what it is driving,
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