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Warco BH600 Non Starter

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Freddie K13/05/2020 23:00:07
3 forum posts
4 photos

Hi all,

This is my first post as I have managed to find the answers I need to most things on the forum. However, I am now stuck!

I have inherited a Warco BH600 lathe which is in fairly good condition. Except for one thing. It will not start! The green light comes on but nothing else happens at all.

So far I have checked the following - plug fuse, machine fuse, chuck guard safety switch, change gear and top cover safety switch, start switch, emergency cut off switch, security of all connections, continuity of all wires, continuity and discontinuity of contactors, contactor coil resistance, transformer output (24v) and wiring diagram as per Grizzly 9249. The Warco wiring diagram is not to helpful.

I have now spent nearly 2 days trying to figure it out. The motor will run forwards or backwards depending which contactor I press. However, when I turn the machine on the contactors do not react and nothing happens when pressing the start button.

If anyone has any sensible suggestions as to what else to try they would be very welcome. I have looked at it so many times I think I have memorised the wiring diagram!

Thanks in advance.10475855-6faf-42b5-b3d7-4585ef97cff8.jpeg


Bazyle14/05/2020 12:43:56
5831 forum posts
216 photos

You do know there is a lever on the saddle that operates the fwd rev switch through the bottom longitudinal bar?
You need to follow the wiring through that set of switches as that will pull in one or other of the fwd rev contactors.
I think.

SillyOldDuffer14/05/2020 13:49:56
7027 forum posts
1549 photos

Not familiar with the lathe, but I'd start by checking the safety interlocks.

My WM280 has three; the NVR engaged, chuck guard must be closed and the panel covering the change gears must be correctly placed. After a while, my chuck-guard came loose on it's pivot and wasn't working the switch inside the headstcok properly: just needed tightening up.

The circuit diagram in the door shows four switches in series at the bottom. K4 looks to be a thermal overload, if so probably on the motor. S5, S6 and S7 are likely to be the safety interlocks. The lathe won't run if any of the four are open. Check for operator error (left a door open...)! Otherwise look for a broken switch, loose connection, or need for mechanical adjustment. The Green Light means the transformer TC and fuse FU1 are OK, and 24V is available. That both contactors work manually suggests 24V isn't reaching them. Check for continuity and volts at each switch with a multimeter.


Freddie K15/05/2020 00:12:05
3 forum posts
4 photos

Thanks for the replies.

Bazyle- First thing I checked. Checked switches for continuity in all positions and 24v feed.

Sillyoldduffer - All safety switches are working correctly. Tested them open and closed. However, you mentioned the thermal overload. I checked that for 24v which it has on both connectors but .......... it is a normally closed circuit and there was no continuity between the two connectors. This may be the problem as it means there is a break in the circuit if there is no continuity between these two connectors at the normally closed connection.

I got a new thermal overload for £18 that is arriving tomorrow and will let you know the outcome.

Thanks again.

Mike Poole15/05/2020 06:48:26
2936 forum posts
70 photos

The control relay K1 which is the black telemecanique one needs to be energised before K2 or K3 will energise to start the motor. I would link out the safety contacts by putting a temporary link from 2 to 21, if the relay energises then you have an open circuit somewhere in the safety chain of contacts. There seems to be a question over the continuity of the contact on the overload so assuming it has been reset with the blue button then just put the temporary link across the contact and see if that energises K1. If the 2 to 21 link does not energise K1 then we need to look at devices 52 and 53, which from what Bazyle says is a switch operated from a saddle mounted lever, if we link 5 to 9 this should tell us if we have a problem with these switches being open. If these checks succeed in energising K1 will the lathe now start?


Ray Lyons15/05/2020 07:34:14
187 forum posts
1 photos

I had a similar problem with my BH600 some years ago. It turned out to be the forward/reverse switch. It is a cam made of a plastic material operated by the control lever. This had come loose, an easy fix but have had no trouble since.

Freddie K15/05/2020 12:59:02
3 forum posts
4 photos

Solved !
It turned out to be a problem in the thermal overload switch where the normally closed circuit was not actually closed. Fitted a new one and now everything is running fine.
Thanks for the help.

larry phelan 115/05/2020 18:30:35
971 forum posts
14 photos

Glad to hear that. I have a Craftsman lathe, very similar to the BH600 and I had trouble with the forward/reverse switches many moons ago. They are quite small, made of plastic [like most other things ] and are easly knocked about. Result--No start !

Have not had any bother YET with thermal overload fingers crossed !

AdrianR15/05/2020 18:53:29
499 forum posts
35 photos

Hmm, I have a BH600, did not know about a thermal overload, useful to know.

A small hint, if you have a 6 pint, milk bottle, the bottom of it makes a really good oil catcher under the gearbox.


Joe Snowden01/01/2021 22:32:05
5 forum posts

Hi All,

Rather than start a new thread, thought I'd revive this one as I'm having a similar problem. I've recently bought a BH600 which I didn't get to see running when I bought it (no reason to doubt the people that I bought it from, selling on behalf of their late father, lovely people).

Since getting it wired in, it has power and I have managed to get to turn the spindle however it's not right. Firstly, in a low rpm gear, it will spin but the motor labour's to get going and sometimes doesn't get up to speed (forward or reverse). If I put it in a higher gear (nothing crazy, 600rpm), I can hear the motor buzz but it doesn't rotate and will eventually what seems like it 'trip' the orange relay and won't energise either forward and reverse relays (albeit I can manual push them in to power the motor). This is all with nothing in the chuck and I am able to rotate the chuck by hand (whilst switched off) with relative ease.

As you may have gathered, I'm far from an electrical expert (or a machinist!) - any advice would be welcomed.

Many Thanks,


Howard Lewis02/01/2021 05:14:52
4662 forum posts
10 photos

If you can rotate the chuck with the belts tensioned, the countershaft and the motor would not seem to be seized. (Selecting maximum speed may make turning the chuck easier for this check )

As a mechanical, rather than electrical engineer, could there be a problem with the start capacitor, or the centrifugal switch on the motor being open circuit and not bringing the start windings into play?


Joe Snowden02/01/2021 14:38:50
5 forum posts

Thanks Howard, I'm definitely leaning towards the motor, is there a way I can test this?

not done it yet02/01/2021 15:39:22
5776 forum posts
20 photos

If it is belt driven from the motor, remove the belt and check it out?

Andrew Tinsley02/01/2021 16:51:08
1335 forum posts

If it is a single phase motor, it sounds as though you may have a dodgy start capacitor (one that has gone low in value.).


Windy02/01/2021 17:13:27
839 forum posts
166 photos

I have the earlier 600 with no gap and had to renew the start capacitor a few times mainly due to stop and start when metric screw cutting.

I did that simple clutch modification for the 600 belts and has made a things easier so very little load on motor if I want to stop and start again.

Howard Lewis03/01/2021 14:32:09
4662 forum posts
10 photos

A new start capacitor should not be an expensive item. The couple that I have bought for my small air compressor and a friend's lawnmower were under £10.

But must be suitable for AC use and rated at about 450 volts.


Joe Snowden07/01/2021 22:49:06
5 forum posts

Just a quick one to report back, I replaced both the start and run capacitors and the problem is resolved, night and day difference.

Of course the disappointing side to this is I no longer have an excuse to upgrade to a inverter/3-phase set up 😁

Many Thanks,


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