Wiring 3 Phase Contactor for 1 Phase Motor?

[Tupers]

I’ve just bought a 3 phase pedestal grinder that’s had a 1 phase motor stuck in it but when it’s switched on it spins anti-clockwise.

Have done a bit of searching it seems that a 3 phase contactor can be required to run a 1 phase motor but how?
I found this write up about how to do it but the connections on my block are numbered vertically not horizontally and I don’t want to go melting anything.
https://www.springercontrols.com/news/single-phase-motor-3-phase-contactor/

Ideally I’d like to keep this contactor as it all lines up with the original switch plate.

 

[carbon]

Is it already running but the wrong direction with the contactor that’s there?

 

[carbon]

If it already runs, changing the connections in the contactor will not change the direction the motor turns. This needs to be done on the motor connections

 

[Tupers]

Yes I can plug it into the wall and turn it on but the motor runs in the wrong direction.

I have removed the negative and positive wire that run to the motor and flipped them but the motor still rotates in the same direction as before.

Do you think there’s something that needs flipping in the motor? I’m going to pop it off now and look for clues.

 

[Seadog]

You need to reverse either the run or the start winding. There should be a wiring diagram on the motor junction box cover.

 

[carbon]

You need to take the connection cover off the motor and see what connections are there. Maybe a diagram to change direction

 

[eddie49]

To me it doesn't look like a cap start motor...
Just 1/6 HP, 1.6 Amps, 1425 rpm presumably geared up for speed, it all seems a bit weak for such a large machine?

 

[dan treg]

as above you need to look at the motor windings not the contactor . some motors can be reversed but not all depends if the field windings are changeable relative to start winding . is there a picture of motor connection or junction box on motor

 

[carbon]

Doesn't look the biggest motor, but possibly original motor size is on the front plate, or current rating

 

[Tupers]

To me it doesn't look like a cap start motor...
Just 1/6 HP, 1.6 Amps, 1425 rpm presumably geared up for speed, it all seems a bit weak for such a large machine?

It could well need a beefier motor it was 3 phase originally so probably would had something more heavy duty in it from new.
I’ve only owned it for 5 hours some I’m just trying to unravel someone else’s ball of yarn now.

There’s no wiring diagram on the motor but under the cover there are three poles numbered 2 3 1.

 

[Tupers]

Here’s the original from plate. It says 440 volt, 3 phase, 50 cycles.

 

[carbon]

On the outside it does state direction is clockwise, not sure connection 3 is connected as would have expected a stud connection. If the belt is in the middle then it may be possible to mount the motor on the other side and reverse the direct that way

 

[mtt.tr]

Not sure motor is big enough assuming its really 1/6hp

 

[brightspark]

couldn't knock the skin of a rice pudding that size. get a minimum of half hp motor on it or bigger the better

 

[Retired]

Hi,

I'd junk the motor and upgrade to at least 3/4hp with correct direct online (DOL) starter; 1/6th hp will struggle to get it moving and eventually burn out. If it has 10" dia wheels I'd upgrade to at least 1hp or even bigger.

The machine is a good quality Denford and deserves sorting out. I wouldn't even play around with such a small power motor.

Kind regards, Colin.

 

[dan treg]

my feeling is motor is internally wired as stated on casing to run in one direction only dont think unless you take motor apart to access wiring you can reverse direction

 

[eddie49]

This similar Viceroy 3-phase pedestal grinder/polisher:
https://www.gumtree.com/p/polishers...estal-mop-polisher-buffing-machine/1353417080
was 3/4 HP, which is 4.5 times more powerful.

 

[Tupers]

So here’s the inside of the motor. Any ideas?

 

[brightspark]

yep get rid and put a decent one on it wont reverse

 

[Tupers]

couldn't knock the skin of a rice pudding that size. get a minimum of half hp motor on it or bigger the better

While it was running I sharpened a 13mm drill and it didn’t bog down but I suspect it’s the polishing that would show the replacement motor up.