What happens if...

[Dieselman 63]

Hello Diesel.

the reason I linked it is that it is a 3/4 H.P. 2840 rpm motor which you said you could not find. And a good price also.

Alec

But then I'd still be at the same place - the motor is 3ph. I have a 3ph 3/4hp motor, it's the one I'm working on. Finding them in single phase is harder, but then I wouldn't have the luxury of speed control. I'm trying to convert the motor to 240 so I don't lose the upper 30% of torque that you do when you hook a 400v motor directly to a 240v 3ph output vfd.

 

[Dieselman 63]

The colours match!

Multimeter purchased, along with a ceramic block for the terminals and a housing which I'll glue to the motor case. All in all, a good day. Now to finish varnishing the string.

 

[piman]

Hello Diesel,

the same company do them in single phase as well. Personally for a grinder I wouldn't bother with speed control, unless you plan using a variety of different sizes or types of wheels?
Good luck with reconfiguring the windings but if it doesn't work out here's a source of 240 to 415 VFDs http://stores.ebay.co.uk/Drives-Direct-Inverters-LTD/DIGITAL-240-TO-415-INVERTERS-/_i.html?_fsub=5&_sid=60949062&_trksid=p4634.c0.m322. I've used them a few times and always had good service. You may find cheaper but this company gives technical back up as well.

Alec

 

[Pete.]

I am pretty sure it doesn't matter a damn which ends of the coils you wire in delta so long as you don't put two ends of the same coil together. If you think about it all you are doing is changing the configuration of the triangle but it still remains a triangle. If it was DC, it would matter.

EDIT: Ok so apparently it does matter. 'phase progression'. There's a simple test to get the coils starts and finishes all lined up described here:

https://www.electriciansforums.co.uk/threads/reconnecting-a-star-delta-motor.17823/#post-129503

 

[Dieselman 63]

Hello Diesel,

the same company do them in single phase as well. Personally for a grinder I wouldn't bother with speed control, unless you plan using a variety of different sizes or types of wheels?
Good luck with reconfiguring the windings but if it doesn't work out here's a source of 240 to 415 VFDs http://stores.ebay.co.uk/Drives-Direct-Inverters-LTD/DIGITAL-240-TO-415-INVERTERS-/_i.html?_fsub=5&_sid=60949062&_trksid=p4634.c0.m322. I've used them a few times and always had good service. You may find cheaper but this company gives technical back up as well.

Alec

The grinder has a water trough on one side which I plan to fit a fine wheel to so that I can sharpen chisels - obviously this needs slow speed to keep it cool, so that's the thinking with the speed control. I want the other wheel to still be used for heavy grinding so being stuck in the hi or lo speed is unhelpful to say the least.

Also you are aware I live in New Zealand? Shipping rates would be through the roof...

 

[Dieselman 63]

The motor is back together.

@spencer 427 This is the same type of motor as you have on your shaper, a Brook Gryphon.

It was tough getting the sides of the bearing race aligned each side of the spindle end with the spring washers inside but in the end I managed it. A torch helps. The old terminal block on the end had two ports blocked up with rubber bits, I've got the star points and the old connections coming out each one, three each side. The bearings are greased up and it feels smooth.

Now I can get back on with the rest of the machine. A big thanks to everyone who has helped me!

 

[Dieselman 63]

Sorted. Motor back together, new housing fitted and the lines going into it (I've yet to connect the star as that has the input). I wrote what the wires were in case someone wants to convert it back to 400v in the future.

 

[Shox Dr]

Cool. That’s the same motor as mine, worth keeping.

 

[Dieselman 63]

Cool. That’s the same motor as mine, worth keeping.

The Gryphon - available up to 1hp and with a range of possible speeds. The one in @spencer 427 's shaper is 960rpm which is a definite non-standard speed. It feels a stout little thing, built to last.

 

[Woody.v8]

Have you put power to it yet?

 

[Dieselman 63]

Have you put power to it yet?

No, no inverter yet. A million projects all on the go at the same time, all begging for money to be spent on them!