VFD Question
- Thread starter Colombo7
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retirede /Besoeker3 ,
Thanks for the replies.
I just realized my mistake in interpreting the table. In fact, pretty much all of the equipment in the new factory uses 400VAC to 110 AC stepdown transformers to supply single phase 110 VAC for their control hardware that is both 50 & 60Hz compatible.
Going back to the motor in question;
230/400V Delta/Wye at 50Hz. (3-Phase Motor)
And looking at the table below;
If my Supply voltage (Grid Voltage based on the highest voltage listed on column 1) is;
200VAC or 220VAC 3-Phase 4-wire grounded Wye,
OR;
Or am I still way off?
And looking at the table below;
If my Supply voltage (Grid Voltage based on the highest voltage listed on column 1) is;
200VAC or 220VAC 3-Phase 4-wire grounded Wye,
OR;
220VAC 3 Phase 3-Wire Delta Connected;
I can connect the above motor in DELTA configuration (per 230/400VAC motor spec)If my Supply voltage is;
380VAC or 400VAC, or 415AC or 440VAC 3-Phase 4-wire grounded Wye,
OR;
440VAC 3 Phase 3-Wire Delta Connected;
I can connect the above motor in WYE configuration (per 230/400VAC motor specification)
OR;
440VAC 3 Phase 3-Wire Delta Connected;
I can connect the above motor in WYE configuration (per 230/400VAC motor specification)
Or am I still way off?
Last edited:
A motor won’t care if the supply is wye or delta as long as the voltages match.
- Location
- San Francisco Bay Area, CA, USA
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- Electrical Engineer
That entirely depends on the nameplate of the motor. Not ALL motors are reconfigurable like that. MOST IEC motors are, but not all. Some are only made with one type of connection for one voltage.
He is mixing up supply issues with motor connection issues. A MOTOR certainly does care whether it is CONNECTED internally as Wye or Delta, because (in IEC motors) that is how the motor voltage is determined.
Reggie Lavoie
Member
- Location
- Wallkill, NY, USA
Match the Nameplate
Match the Nameplate
Motors are designed to operate at a certain frequency and voltage. As long as this voltage to frequency ratio is maintained, the motor will be able to provide full torque. For example, if a three phase 460 volt motor is designed to operate at 60 hertz, it will also provide full torque at half of each (230 volts at 30 hertz). This also means that this same 460 volt motor will also operate fine at 380 volts, 50 hertz. Remember that even though it can still provide full torque, the HP drops because the RPM drops (HP = torque x RPM / 5252). If you follow this principle on your 3 phase motor, you should be fine. One thing to keep in mind is cooling. At lower RPMs the motor fan spins slower, resulting in less cooling. In a constant torque application (like a conveyor belt) additional cooling may be required at lower RPMs (such as an additional blower on the motor). In a typical centrifugal fan application, the torque is much less at lower RPMs so it may not require additional cooling unless going below 10 hertz.
Match the Nameplate
Motors are designed to operate at a certain frequency and voltage. As long as this voltage to frequency ratio is maintained, the motor will be able to provide full torque. For example, if a three phase 460 volt motor is designed to operate at 60 hertz, it will also provide full torque at half of each (230 volts at 30 hertz). This also means that this same 460 volt motor will also operate fine at 380 volts, 50 hertz. Remember that even though it can still provide full torque, the HP drops because the RPM drops (HP = torque x RPM / 5252). If you follow this principle on your 3 phase motor, you should be fine. One thing to keep in mind is cooling. At lower RPMs the motor fan spins slower, resulting in less cooling. In a constant torque application (like a conveyor belt) additional cooling may be required at lower RPMs (such as an additional blower on the motor). In a typical centrifugal fan application, the torque is much less at lower RPMs so it may not require additional cooling unless going below 10 hertz.
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