Lathe electrical drawing

This topic has 4 replies, 4 voices, and was last updated 3 October 2020 at 23:50 by Clive Foster.

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3 October 2020 at 07:16 #499225
Chris Reid 1
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@chrisreid1
Hi,

I am wondering if anyone can help me with an electrical drawing of a SAN YUEN SG- SAG 1800 Lathe??

Someone has been in and messed with the wiring, I have the lathe turning fwd and rev that's ok, but its the footswitch stop that I cannot get to work, if you press your foot on it it does stop but lift your foot it stars again but it should stay dead as an emergency stop.

The lathe is turned on by the handle, up is fwd and down is rev, now this is a latching switch, the lever is up and the contactor coil is energised (the contactors are not wired for self-latching) The footswitch is a momentary switch and does not latch like a mushroom emergency off switch, so there is the problem I need a circuit that will override the latching on switch with a non-latching foot off switch, there is a 3rd contactor in the box I think this was used for the foot off switch but the wires are all disconnected and I can't get my head around how it should be wired !!

Chris
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3 October 2020 at 07:16 #27674
Chris Reid 1
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@chrisreid1
San Yuen SY-SAG1800
3 October 2020 at 14:45 #499319
not done it yet
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@notdoneityet
Change the emergency stop to one that does latch?
3 October 2020 at 18:14 #499358
Brian Sweeting 2
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@briansweeting2
Shouldn't the foot switch only enable the motor when there is a foot on the pedal, rather like a dead man's handle?
3 October 2020 at 23:50 #499414
Clive Foster
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@clivefoster55965
Chris

Might be worth looking at the Grizzly Tools website to see if they offer a similar machine and, if so, downloading the manual for a circuit diagram. Grizzly manuals are generally reckoned to be about the best for the Asian import machines.

Generally the Asian machines of comparable size and duty class use very similar electrical circuit arrangements. Even if not exactly the same machine its possible that an equivalent from Grizzly has a sufficiently similar circuit arrangement for you to figure out what you have.

If you have separate motor start and stop buttons independent of the forward and reverse switch its possible that the 3 rd contactor should be wired to provides the self-latching and safety release functions. Basically the motor incoming power goes via the 3 rd contactor connected in the usual way with momentary close and open start and stop switches to operate the coil with the usual monetary break safety switches in series with the stop switch.

I guess the lathe doesn't have a clutch. Just push the start button to get power up to the motor control contactors then select forward or reverse. Not a nice system with the latching switches for forawrd and reverse.

My Smart & Brown 1024 VSL is a clutchless machine and uses a system very similar to what I've described but all the switches are momentary. The latching control contactor also provides a spindle jog function so it turns only when a forward or reverse button is held down.

Clive

Clive
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