From what I can see in your unloading picture it is a "Varidrive" machine. I have one of these running from a VFD at 230/240 Volts.

Dual voltage, not 2 speed. It needs 415V in star and 230V in delta. Should be a box on the motor with internal links to change between star and delta.

Andrew

I've taken apart quite a lot of single and three phase motors, but I don't claim to be an expert. As the data plate states this can be wired for 220v or 380v operation then it should be possible to change some links somewhere. I suspect if you open the motor up you'll find links behind the wiring box. If so, you should be able to wire for delta operation.

As an aside, here are two good books you may find useful.

Electric motors (16) and electric motors in the home workshop (24) in the workshop practice series.

That is a remarkably crude data-plate.

Normally motors capable of being configured in both Star and Delta have 6 terminals in the junction box witha set of links to get the coils in the appropriate order.

In the UK permanently wired motors on things like machine tools, especilly older ones, are commonly wired Star for 420 volts so changing needs digging into the internal wiring. Usually the data plate simply states 420 volts but I have encountered a couple that had details for 230 volt Delta connections on the data the plate as well with a simple punch or similar mark to identify which way the internal connections were set.

The first time I encountered such a motor I was unamused to find hard soldered connections after opening it up instead of the expected set of screw terminals to facilitate re-configration hidden under the junction box. It took a fairly forensic examination of the, somewhat aged, data plate to discover the indicating puch mark.

If you are lucky the reconfiguration connections will be on the back side of the visible board. Not something I've seen but I'm told it has been done.

Clive

Colin

Although more modern motors have 6 terminals and usually brass jumper link some early motors had just 4 terminals. Each of the wires from the windings, there should be 6 in total, will be identified either by colour or some other form of marking. Note down what the connections are at the moment for use later.

For 380/420V (Hi Volts star connection) three wire from the winding would be connected to one terminal to form the star point and each of the other ends of the 3 windings would be connect to a single terminal to which the three phase supply is connected. This is most likely the connection arrangement you have at the moment.

For 220/240V (Lo Volts Delta connection) operation the three windings are connected effectively in a ring. So the end of one winding is connected to the start of the next winding.

However how does one know what are the start and finish of each winding if the motor doesn't have a circuit diagram on the terminal box cover. The three wires connected to the common star point , if connected for Hi Volts, are likely to be the finish of each winding.

So begin by isolating each wire from the star point and then use an ohm meter to find the match start of each winding and note the colour.

Clive Steer

Colin

If the motor is wired for star and cannot be altered easily it will run on Lo Volts 3 phase but develop a quarter of the torque but probably sufficient for testing. The speed will be right whatever voltage the motor is feed with except for a more slip at the reduced torque.

Clive

Andrew

Inverter Drive Supermarket have a nice blog post covering running a 400 V (nominal) star connected motor from a 230 V (nominal) inverter.

**LINK**

https://inverterdrive.com/HowTo/240V-Supply-to-a-400V-AC-Motor/

Basically you get full torque up to 29 Hz where the motor runs at 2/3 rds the nameplate speed so you do indeed get 60 % of the power. Theoretically 2/3 rds, 66 % but I imagine there are various detail devils deciding exactly how much.

Moi?

I'd work on 50 % of nameplate power and expect a healthy safety margin to exploit.

Hmm. Wonder how much air a Hydrovane makes at 2/3rds speed?

Clive

Edited By Clive Foster on 17/01/2022 17:59:00

Edited By Clive Foster on 17/01/2022 18:11:19

G&M Tools   Apologies, Project Machinery have a used Transwave 1.2 Kw phase convertor listed, 415 output, £ couple of hundred.. ..an use?

Edited By DiogenesII on 18/01/2022 10:01:26

Andrew

I suspect the confusion about torque and power loss was due to thinking in DC motor terms where half the voltage means half the current which means half the torque then if running at half speed you have 1/4 power. Or something of that lik.

Clive