Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 15 of 18
Thread: Electrical problem with a lathe
-
29th Aug 2012, 03:16 PM #1
Electrical problem with a lathe
G'day All.
Went to use the lathe yesterday and all it would do is the chuck would rock backwards and forwards.
It is a 3 phase 3HP pacific.
I pulled the cover off the electrical area and put the test meter on the 3 wires coming in. I have 240Volts at each of the 3 wires.
The contacters for forward and reverse have power to all 3 output connectors.
The strange thing is that the 3 phase coolant pump will not run either.
Other than getting a sparky in to check it out, anyone have any ideas?
Thanks.Hooroo.
Regards, Trevor
Grafton
-
29th Aug 2012, 03:38 PM #2Philomath in training
- Join Date
- Oct 2011
- Location
- Norwood-ish, Adelaide
- Age
- 59
- Posts
- 6,540
(With the power disconnected) have you resistance across each of the windings?
If it was single phase I'd suggest the start coil had burnt out, but with 3 phase??
Michael
-
29th Aug 2012, 05:26 PM #3Most Valued Member
- Join Date
- Jul 2006
- Location
- Athelstone, SA 5076
- Posts
- 4,255
I assume its standard 3 phase
measuring to earth can result in back feed thru windings giving the impression that you have all phases...ideally measure across 3 lots of two phases at the bottom of the contactor...ie
red to blue
blue to white
white to red
each reading should show 415V or there abouts
make sure the motor has equal resistance across all three windings
-
29th Aug 2012, 05:39 PM #4Senior Member
- Join Date
- Mar 2009
- Location
- Robertson NSW
- Posts
- 133
I had a problem similar to that many years ago on my Takisawa (not sure if it was exactly the same problem) but what caused it was at the headstock end of the forward/reverse/stop lever the cams that work the switches had come loose and weren't doing their job properly, just follow the rod along(if you have one) and where it goes into the headstock base remove the cover and have a look-WITH THE POWER OFF, you will be able to work out if the cams are loose.
Will
-
29th Aug 2012, 06:09 PM #5
The forward reverse rod and cam have 2 limit switches and they are working OK.
It seems strange that the Coolant pump isn't working either.
I might wire the power lead directly to the motor and bypass all the contactors and see if she will spin.Hooroo.
Regards, Trevor
Grafton
-
29th Aug 2012, 08:34 PM #6
Sounds like you've lost a phase, and somewhere upstream I'd guess if the coolant pump isn't running either.
Regards
Ray
-
29th Aug 2012, 08:53 PM #7
Thanks, Ray.
A mate is coming to have a look on Friday.Hooroo.
Regards, Trevor
Grafton
-
29th Aug 2012, 09:01 PM #8Most Valued Member
- Join Date
- Apr 2012
- Location
- Healesville
- Posts
- 2,129
I thing RayG might be on the right track there.
I sometimes have a machine that will just hum when I switch it on and all I do is push the plug into the socket a bit firmer.
-
4th Sep 2012, 04:43 PM #9Most Valued Member
- Join Date
- Jul 2006
- Location
- Athelstone, SA 5076
- Posts
- 4,255
-
4th Sep 2012, 06:57 PM #10
Mate couldn't make it.
The sparky that fitted the new main switch to the meterbox is coming back this Friday to fix his FUBAR...
I'll let you know the outcome.Hooroo.
Regards, Trevor
Grafton
-
5th Sep 2012, 08:41 AM #11Most Valued Member
- Join Date
- Jul 2006
- Location
- Athelstone, SA 5076
- Posts
- 4,255
-
5th Sep 2012, 06:51 PM #12
-
6th Sep 2012, 08:26 AM #13Most Valued Member
- Join Date
- Jul 2006
- Location
- Athelstone, SA 5076
- Posts
- 4,255
-
7th Sep 2012, 11:40 PM #14
Well. Mystery solved.
The sparky rocked up this morning and looked over everything. When he fitted the new 3 phase main switch, he placed 2 active wires for the shed main switch into the same active connector. Thus I only had 2 active phases in the shed. but when you placed a test light across the 3 actives in the shed it showed that they had power. but when the test light was put from active 1 to active 2 there was no light.
So now the lathe is operational again and turned up a few nylon spacers today.
Life is good with 3 phase.....Hooroo.
Regards, Trevor
Grafton
-
7th Sep 2012, 11:54 PM #15Diamond Member
- Join Date
- Oct 2008
- Location
- N.W.Tasmania
- Posts
- 1,407
Now that should be worth some discount for all the inconvenience he caused, and the lost time etc. I'm glad that's all it was though.
Rob.