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motor questions 1
- Thread starter kasco
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It all depends on the load that the motor is spinning.
If it's a 1 HP load, it will be about 1 kW power input, or 1 kWh energy use in one hour.
Someone else may comment on the relative efficiency of the conditions you described. They won't vary a lot, though.
Best to you,
Goober Dave
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If it's a 1 HP load, it will be about 1 kW power input, or 1 kWh energy use in one hour.
Someone else may comment on the relative efficiency of the conditions you described. They won't vary a lot, though.
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
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Watts = watts = watts. Phase, speed, Hz, none of that changes anything. 746W = 1HP
An motor only draws as much power as the load requires. Absorbed power (the electrical energy used from the source) = Load power / efficiency. So unless you know the efficiency of the "1HP motor" and the actual required power that the LOAD requires from the motor (assumed to be less than 1HP in your example), you cannot tell anything else yet with regards to absorbed power.
You can make ASSUMPTIONS however: If it is an older motor, it's fairly safe to assume 80% efficiency. If it is a newer motor, assume 95% efficiency. Single phase motors tend to be slightly less efficient that 3 phase, but at 1HP that may not be a safe assumption, it can co either way. But still, without knowing what the LOAD is actually requiring at the speed you run at, that is a pointless exercise.
By the way, "HP" is a shorthand abreviation of "XX torque at YY speed". So to ask whether a 1HP motor absorbs more power at 100RPM or 1000RPM is by itself a pointless discussion, because you are STARTING from the standpoint of ALREADY having dictated the HP either way. 1HP at 100RPM is still 1HP at 1000RPM, the TORQUE however will be different by a factor of 10. If however you are planing on starting with a 1HP 1000RPM motor and then VARYING the speed down to 100RPM with something else, like a VFD, that's a different matter. But you made no such statement, and again, that discussion will still be load dependent.
Maybe if you describe the reason you need to know this, we can assist in getting to real information for you.
"Will work for salami"
An motor only draws as much power as the load requires. Absorbed power (the electrical energy used from the source) = Load power / efficiency. So unless you know the efficiency of the "1HP motor" and the actual required power that the LOAD requires from the motor (assumed to be less than 1HP in your example), you cannot tell anything else yet with regards to absorbed power.
You can make ASSUMPTIONS however: If it is an older motor, it's fairly safe to assume 80% efficiency. If it is a newer motor, assume 95% efficiency. Single phase motors tend to be slightly less efficient that 3 phase, but at 1HP that may not be a safe assumption, it can co either way. But still, without knowing what the LOAD is actually requiring at the speed you run at, that is a pointless exercise.
By the way, "HP" is a shorthand abreviation of "XX torque at YY speed". So to ask whether a 1HP motor absorbs more power at 100RPM or 1000RPM is by itself a pointless discussion, because you are STARTING from the standpoint of ALREADY having dictated the HP either way. 1HP at 100RPM is still 1HP at 1000RPM, the TORQUE however will be different by a factor of 10. If however you are planing on starting with a 1HP 1000RPM motor and then VARYING the speed down to 100RPM with something else, like a VFD, that's a different matter. But you made no such statement, and again, that discussion will still be load dependent.
Maybe if you describe the reason you need to know this, we can assist in getting to real information for you.
"Will work for salami"
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