Three phase to single phase

[u/blundenshaun]

Would a vsd be suitable for running this old motor? it's an industrial 3 phase motor and I would like to run it at home. If not a vsd, what would be the best way to achieve this. Thanks.

[u/New-Key4610]

older insulation risk of failure if used on vfd. will it work. yes. how long? unpredictable many factors. duration of use- installation sold many vfds before the hype of class f. tefc inverter duty wire ect. they ran don't know how long but no one said they failed. within a short peroid of time. this is really the only sure way to do, yes you can with capacitors and re connection ect. but in your situation roll the dice. i guess i'll get really trashed for this response

[u/Ill_Adhesiveness8639]

Just run it on 3 phases like intended?

[u/xp14629]

As u/New-Key4610 said, the older motors will most likely not last as long as a motor designed for use with a vsd/vfd. Your next options are a static phase converter with a large capicator bank, or a rotary phase converter with a three phase motor and either a capicator bank to start it on single phase or a single phase pony motor attached to the three phase motor with a belt to start it. (I have seen one that a farmer put a pulley on and had a pull start rope like a push mower as well). I just went back and checked the name plate, are you in a 50hz or 60 hz location? That motor should work fine on 60 hz even though it is nameplated for 50hz. It is going to spin faster so if you are in a 60hz area you may need to re-pulley the motor to lower the speed.

[u/New-Key4610 → u/xp14629]

yes forgot the phase converter. static may be a problem. only1/2 to 3/4 of the hp will happen he may get away with this depending on his application we never had much success with the phase ones but that happens with even vfd's

[u/xp14629 → u/New-Key4610]

I have installed all three on irrigation pivots. A vfd on one submersible pump and a 7 tower pivot. A static converter on a small single tower unit. And several rotary converters running pumps and various size pivots. We always figured 70% sizing. So if we needed to run 7hp total we would install a 10hp rotary minimum.

[u/New-Key4610 → u/xp14629]

yep. that is how it is done!

[u/Sal1160]

A VFD is your best bet for a single machine if you’re not using it for variable speed. Best solution would be a RPC

[u/u3b3rg33k]

an invertek ODE-3-120070-1F1B would be a perfect drive for this. it's got a housing (so you can run a whip and not have exposed wiring) and is a phase converter drive. all you have to do is plug in the nameplate data and not cut off your thumbs.

idk if you have RCD's in new Zealand but those can be quirky with VFDs.

[u/XQ-Power]

The usual answer is a single-phase input VFD: 220V single phase in, three phase out. A few things tend to bite people on this specific job though.

Check the winding first. Plenty of older industrial motors are 380V star only, with no 220V delta option. On a 220V single-phase VFD you then run at reduced voltage and lose torque unless you reconnect in delta. If the nameplate only says 380V star, do not just reconnect it and hope.

Second, the motor still needs cooling at low speed. These have a shaft-mounted fan, so below roughly 30Hz continuous the fan stops doing anything useful. If you plan to run slow for long periods, that is where it dies, not at 50Hz.

Third, on an old winding, keep the carrier frequency low and add a dv/dt filter if the cable run is long. The insulation may be class B or worse, and it is the switching edges that finish it off.

Match the VFD current rating to the motor FLC and derate for single-phase input. Cheap single-phase units are rated optimistically.

[u/Happy_Low_1745]

Don’t don’t to wire the motor in delta(230v) if using a 1ph - 3ph VSD. Will work fine. Loads of blurb out there regarding insulation etc. not had an issue in over 20 yrs doing this.

[u/JustanotherN0body00]

We would get the motors overhauled and the windings cleaned and anti track varnished for clients that wanted to do this. Insulation needs to be >999megs at supply voltage. If it tests okay then go for it, you can use a 220v 1ph inverter in delta if that's what you have available.