Need help with 415V motor
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  1. #1
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    Default Need help with 415V motor

    I've purchased a dust extractor that's 3 phase 415V. Understanding I can get an autotransformer and run a VFD. Before I do anything though I wanted to find out if I can run it at 240v 3 phase with a VFD.
    Can't find any details on the motor whatsoever, just info off the data plate from the extractor itself.

    Can anyone give me some advice on how I can tell if it's dual voltage, if possible in layman's terms. I understand electrical to a degree but am far from an electrical engineer, still learning as I go.

    Thanks for your help.

    I have some photos but still trying to work out how to upload them. First time posting.

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    if it has just 3 wires, it is NOT dual voltage. It takes 6 wires to be dual voltage, minimum. If it cannot be set for a lower voltage, then you really are not going to get much out of it at 220V.

    The 415V is a 50Hz voltage, equivalent to 480V 60 Hz. You could run it on that, and it would be fine. If the transformer were supplied by a VFD, then it would run the motor.

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    To amplify on that, Take the cover off the motor's junction box. If there are only three terminal posts then it's a fixed 415V motor and you'll need a 240V VFS and a thee phase 240/415V transformer or a 240/415V transformer and a 415V VFD that cann accept a single phase input.

    If the connections in the motor are to 6 terminal posts with links between three of them and the power connected to the other three, then it can be converted to 240V by moving the links so they connect the two rows of three posts together with their opposite posts.

    Like on this page:- Electric Motor Terminal Box Connections

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    I think you folks have your pole count wrong. Each field coil has two ends (two wires). Each pole has two coils (four wires). Three poles, 12 wires. They are wired in series for high voltage and in parallel for low voltage. There usually is a wiring diagram on the motor wire box cover.

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    This is actually getting interesting. Every three-phase dual voltage motor I've ever used (all were 240/480) had 9 wires number H1 through H9. The motor data plate normally has the connection diagram showing the proper hookup for both voltages.

    To answer OP's primary question, "I wanted to find out if I can run it at 240v 3 phase with a VFD", JST said "The 415V is a 50Hz voltage, equivalent to 480V 60 Hz. You could run it on that, and it would be fine." I concur, and so the answer is yes, just use a VFD that outputs 480v three phase and it will run fine.

    If the motor is made for 50 HZ, won't the rotation speed be 20% higher at 60 HZ though?

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    You are both talking about US motors designed for the rather odd supplies that you have.

    This will be a standard thee phase 415V motor that has three windings. They may be connected star (wye in the US) or delta. If the motor is single voltage, there will be three wires with the star point inside the motor (although it can normally be found and brought out). If it is designed for operation on two voltages, both ends of the windings are brought out and can be connected either star or delta to give 415V or 240 (=415/√3).

    60Hz is irrelevant, Australia uses 50Hz, which the motor is rated for.

    You should be aware of this Steve-I, given your location.

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    As mentioned above, dual-voltage European motors (IEC frame) are typically made in 6-lead star/delta configuration for 240/415V operation. Dual-voltage North-American (NEMA frame) motors are typically sold in 9-lead series/parallel configuration for 240/480V operation.

    Some older NEMA motors can still be found in 12-lead configuration for star-delta starting, but they are generally no longer specified in the US thanks to the advent of electronic soft starters and VFDs. Much simpler and cheaper to just slip an electronic dongle in series with the motor leads than to muck around with three separate contactors and six leads down to the motor and back again. NEMA contactors in the US are VERY expensive compared to the IEC ones used overseas.

    If it is single voltage it will only have three leads and a ground screw - EU or NA.

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    Quote Originally Posted by steve-l View Post
    I think you folks have your pole count wrong. Each field coil has two ends (two wires). Each pole has two coils (four wires). Three poles, 12 wires. They are wired in series for high voltage and in parallel for low voltage. There usually is a wiring diagram on the motor wire box cover.

    Six wire european motors (that would be expected to be made for 380 or 415V) are 6 wire specifically for the 220/380 delta wye voltage change (may be 240/415V in the UK). That is pretty much the fewest wires that will change voltage on a 3 phase motor.

    Series coil US motors that do 220/440 changes are as you say, at least 9 wire motors. The 9 wire have one set wired permanently wye, plus 3 "floating" coils.


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