3 Phase Induction Motor ( 195 V - 3,7 A - 290 Hz ) How to operate

An induction motor needs AC as the rotor is just a set of copper bars and they need AC in the stator windings to induce current in them, so there are separate magnetic fields in the rotor and stator to work against each other.

They also need some way of defining the rotation direction - three phase inherently does that, though can get them to turn on single phase by connecting two terminals to the supply and a suitable capacitor from the third terminal to one or the other supply terminals. The power is rather lower, in a motor not designed to work like that.

The frequency on the motor will be for its maximum speed (17000 RPM). It can run far slower, but the voltage needs to be reduced as well to prevent it overheating.

The original control board would include a rectifier, smoothing and a three phase H bridge style driver, to create a three phase power output with variable frequency and duty cycle.

The motor also has a tachometer on the back that the control board would use to monitor the speed and adjust the frequency and duty cycle (in effect, current control) to hold the motor at whatever speed was commanded.

You cannot use them on low voltage DC.

Remember that the output power of a motor or engine relates to both torque and speed - it will only give full power at rather high speeds, into the thousands or RPM, so they are unfortunately not very practical for anything that needs low speeds or high torque.

Just to put it in perspective, at full speed (17000 RPM) that motor which is approximately 1HP, gives about 0.4 nm which is also about 0.4 oz-in torque.

You can give over ten times that just gripping and turning something between the tips of your thumb and first finger.

The difference is of course that if you geared down the motor speed to eg. 60 rpm, its torque would be near 115nm (about 10Kg on a one meter lever) and possibly enough to twist your arm off..

The hard part is gearing down from the ludicrously high speeds they use, without it costing far more than a low speed motor that is easier to power and control.

rjenkinsgb said:

The frequency on the motor will be for its maximum speed (17000 RPM). It can run far slower, but the voltage needs to be reduced as well to prevent it overheating.

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The voltage has to be reduced to keep the same ratio between voltage and frequency.

It's rated at 195 V at 290 Hz. That would be 33 V at 50 Hz. You may be able to get away with a little more voltage than that.

The power will also be reduced by the same ratio. The maximum current is unchanged. The motor would probably work when connected to a 30 V, 4A transformer and a starting capacitor. If you've got a suitable transformer, and you don't mind spinning the motor by hand to get it started, it will probably rotate without a starting capacitor.

You can also pick up the cheaper Huanyang VFD's that should be able to run it.

I suppose, then, that there are no free drawings for something like this (a. and b.)?

gio4 said:

I suppose, then, that there are no free drawings for something like this (a. and b.)?

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Running from low voltage DC (b) is difficult.
Running from AC mains is just a matter of connecting one of these or similar:- https://www.ebay.co.uk/itm/143687665423

The connections are quite simple. The ebay listing says:-
R.S.T:Input terminal of AC line power.（220V class for single phase, single phase connected to any two phases）
U.V.W:Output terminal of the inverter

So you just connect mains to any two of R, S and T. The motor wires are the three blue ones, so don't connect to the two red wires that go the speed sensor.

Make sure you connect the motor frame and the inverter earth connection to ground.

You need to tell the inverter that the motor is rated at 290 Hz, and 195 V. I have a similar inverter and it works well but I found it a bit frustrating to set up. It's described here:- https://www.electro-tech-online.com...e-phase-motor-from-single-phase-mains.161572/