CO632 lathe with no contactors

[AlfromNH]

I just got this Yangzhou TY-CO632 Metal Lathe(sorry, no pics of it in my shop). In contrast to every other pic I’ve seen of this model lathe, mine has no control panel. No pilot light, jog button or estop button. No transformer, relays or contactors. It’s just 210v -> spindle switch -> motor.

Is it likely this is the way it came from the factory? Maybe a lower priced model?

Are there reasons I should consider adding the extra electricals? I’d like to have the features, so there’s that…

 

[graham-xrf]

I just got this Yangzhou TY-CO632 Metal Lathe(sorry, no pics of it in my shop). In contrast to every other pic I’ve seen of this model lathe, mine has no control panel. No pilot light, jog button or estop button. No transformer, relays or contactors. It’s just 210v -> spindle switch -> motor.

Is it likely this is the way it came from the factory? Maybe a lower priced model?

Are there reasons I should consider adding the extra electricals? I’d like to have the features, so there’s that…

If you already feel "it would be nice" to have a E-stop safety button, then surely do go ahead. There are folk here who have wired up all manner of controls and features. From your description, I guess it has a single phase induction motor, but do check. Does it have a capacitor. (I would squirm a bit if it has brushes).

It looks quite big, so it would be useful to know the motor power. All the features you like, plus built-in electrical overload, and torque-limit trip-out can be had with a modern VFD, although the pulse-width modulated motor drive technology has long surpassed what "VFD" used to mean. Safe, low voltage wiring to switches is what I like, and what I am installing. The ability to program in controlled acceleration to a variable set speed, and decelerate to a swift, and smooth, but not gear-wrenching stop is also what I like.

If not VFD, then I use solid state SSR in place of traditional contactors, and a common wall-wart 500mA or so DC supply for the little latching relay. I was into exactly this a few days ago.



Sorry - the sketch was a bit scrappy. I am sure you can come up with your version, but I was thinking a VFD, though not essential, would be nice. It would also give easy, safe switching to select reverse.

 

[AlfromNH]

thanks for the reply. the motor is single phase, with two capacitors. The nameplate got lost somewhere along the line, but it’s big and heavy, 2hp?

I found this label inside the wiring housing, it’s the only printing I’ve found.

 

[markba633csi]

220 volts would be best for a motor that large no matter what type of switching you end up using
I wouldn't try to run it on 110v

 

[TorontoBuilder]

IF this were my lathe, well I'd not use it without an emergency stop.

I'd want a foot brake in that size, but appears to be none, so I'd want to install either a mechanical brake or at least DC injection braking.

Jog is so handy as well.

I guess that is why I wired my last lathe to have forward, reverse, jog forward, jog reverse, e-stop and dc injection braking all thru a series of safety switches and VFD. But that's just me.

You may just want to add a transformer and low voltage circuit for safety switches and contactor, maybe interlocked contactors to change spindle direction and have at er.

 

[TorontoBuilder]

If you already feel "it would be nice" to have a E-stop safety button, then surely do go ahead. There are folk here who have wired up all manner of controls and features. From your description, I guess it has a single phase induction motor, but do check. Does it have a capacitor. (I would squirm a bit if it has brushes).

It looks quite big, so it would be useful to know the motor power. All the features you like, plus built-in electrical overload, and torque-limit trip-out can be had with a modern VFD, although the pulse-width modulated motor drive technology has long surpassed what "VFD" used to mean. Safe, low voltage wiring to switches is what I like, and what I am installing. The ability to program in controlled acceleration to a variable set speed, and decelerate to a swift, and smooth, but not gear-wrenching stop is also what I like.

If not VFD, then I use solid state SSR in place of traditional contactors, and a common wall-wart 500mA or so DC supply for the little latching relay. I was into exactly this a few days ago.

View attachment 427834

Sorry - the sketch was a bit scrappy. I am sure you can come up with your version, but I was thinking a VFD, though not essential, would be nice. It would also give easy, safe switching to select reverse.

I love sold state relays, but only where used appropriately.

Most SSR manufacturers have a prominent statement similar to this at the very beginning of their documentation for a reason:

SSRs use semiconductors, and semiconductors may commonly malfunction or fail. Short-circuit failures represent the main failure mode and can result in an inability to shut OFF the load*.

Therefore, for fail-safe operation of control circuits that use SSRs, do not use circuits that shut OFF the load power supply only with an SSR, but rather also use circuits with a contactor or breaker that shuts off the load when the SSR fails.

*Note: This is not a very desirable outcome in a 13x40 lathe swinging a nice chunk of steel...

 

[Ulma Doctor]

if you are going the SSR route, you'll need to appropriately size them

 

[graham-xrf]

I love sold state relays, but only where used appropriately.

Most SSR manufacturers have a prominent statement similar to this at the very beginning of their documentation for a reason:

SSRs use semiconductors, and semiconductors may commonly malfunction or fail. Short-circuit failures represent the main failure mode and can result in an inability to shut OFF the load*.

Therefore, for fail-safe operation of control circuits that use SSRs, do not use circuits that shut OFF the load power supply only with an SSR, but rather also use circuits with a contactor or breaker that shuts off the load when the SSR fails.

*Note: This is not a very desirable outcome in a 13x40 lathe swinging a nice chunk of steel...

Not shown in the crappy little sketch, but for me, regardless what kind of switching or controls are downsteam, I always have a mains isolator switch that will definitely remove all energy. Induction motors produce crazy voltages when the switch goes off, but the motor is still turning. These can be injurious to semiconductor switching. Also, the start-up current surge can be several times larger than the motor running rating. For a 2HP motor, nominally 1492Watts, let us round that to 1500W. Then for 235VAC, calculate about 6.4Amps. It might be 7 or 8 Amps in practice. For this, I use a 40Amps or 63Amps rated breaker, and I look for it to stay viable in the face of around 1kV voltage spike. Also, I use a big heat sink.

Call it OTT if you like, but I have never yet had a SSR short-circuit stuck-on-state failure, and I was messing with them for more than 2 decades. Things can get quite elaborate if one uses 2-stage starts, resistive damped run-up, and resistor-braked stopping, but for a little 2HP or 3HP motor, things are not so tricky. Definitely the full safety-rated VFDs or servo drives can now guarantee no voltage arrives if the E-stop is in, even without upstream safety relay driven contactors. The makers claim one can disconnect and service or replace motors. I don't have the nerve, nor the need to do that, when the isolator is right there, and so easy to use.

Also, VFDs have soft starts, without wild current transients, which I like.

 

[phranticness]

Personally, I'd be ok with a drum switch.

 

[AlfromNH]

Thanks for the input, guys. I’m new to this(obviously) but I’ve been reading up on VFD’s. So basically it would eliminate the need for a transformer and contactors, and give me wiring connections for estop, pilot light, jog button?

It would also give me speed control so I could adjust the speed while the machine is running, as opposed to the gearbox which requires the spindle to be stopped to adjust speeds? What do people normally do, just leave the gearbox in a middle gear and use the vfd?

I‘m sure there are multiple threads covering all this, I should probably just keep reading…