Can anyone help me, I need to work out the required amps for a 7.5 horsepower, 3 phase compressor. Thanks.
- posted
19 years ago
Determining amps for compressor
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- posted
19 years ago
1) check the nameplace OR
2) WAG it by ASSuming 1kVA per HP divided by the three phases.
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- posted
19 years ago
Should be on the nameplate. What's the voltage?
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- posted
19 years ago
Table 430.150 has that HP listed as
24.2 Amps - 208 Volts 22 Amps - 230 Volts 11 Amps - 460 VoltsNate
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- posted
19 years ago
Hello there
Judging by your email address I would say you are in Australia? Most 3 phase motors operating here of that size are 415 volt. A real rough and ready way to calculate the amps per phase for 415 volt 3 phase motors is just to multiply the power rating in kW by 2. Gets you in ball park range for most motors under 200kW. This is definately not how they teach you to do it, but it gets pretty close. So say a 15kW motor - 15*2 = 30 amps per phase. (the 15 kw motors I have seen have a current rating on the plate of around 28-29 amps per phase).
Assuming your motor is 3 phase 415 volt, I would estimate the current to be around 12 amps per phase. As other posters have said the only real way to know if to look at the plate on the motor.
cheers James