Monarch 12CK Power

Was able to assist a friend in "rescuing" two Monarch CK lathes, one is a 12 inch and the other a 14 (i think), Both were destined for the scrap yard and were disconnected from power and "stored" in an open ended connex.

No wiring diagram or schematic on either of these 1941 model lathes, and we're trying to figure out the proper way to power them. Three phase power is available.

Neither lathe had power cables, and both motors had been disconnected from the switches.
Motor leads are intact and still have lead numbers on them. however cabling from switches was cut at back of lathe.

I'm by no stretch of the imagination an electrician, but all modern 3phase motors I work with have some sort of motor starter, even my 1941 Hendey has some type of mechanical relay/ motor starter, these have nothing. Or if they ever did the previous owner, scrapped them instead of storing them with teh lathes.

Can anyone provide the connection details or a wiring diagram on how to correctly connect power from line to lathe including having a functional fwd / rev switch? were motor starters used?

I've done web searches and looked at Vintage Machinery and Lathes UK, with no success.

Any assistance would be greatly appreciated.

I reached out to a couple of guys that I know with larger Monarchs, to see it they have a wiring diagram that they can share.

Cal

I just brought home a CK 12x54 from 1945 and I will take any pictures I can of the wiring if that will help. Mine has 110 volt controls and the standard push button station on the front.

Neither of my contacts have a wiring diagram for their lathes, but assuming that you just have a 3-phase motor to start, stop and reverse, it's pretty straight forward. There's a number of ways to go, depending on what you plan to do with the machines and what power source you have available (i.e. 3-phase, rotary phase converter, or single phase).

The industrial wiring solution would include:

• fused disconnect
• two magnetic starters (forward and reverse)
• interlock between starters
• overload device

Here's an example:

There's other ways to wire this up. The above uses 24VDC, but it's possible to use 240VAC coils in the starters so that you don't need the 24VDC power supply. Outfits like Automation Direct have all the parts. The fused disconnect is about $90, starters are $60 each, interlock is $15, overload device is $65. By the time you add the switches and a box to mount everything in you're probably getting up in the neighborhood of $400 for the parts.

Another option is to use a VFD. You can get an import, 10HP rated VFD on eBay for $175, but you take your chances there. rakort is using a 5HP eBay VDF with his 10EE drive; so far, so good. 10HP VFDs from Automation Direct, etc., are a lot more.

Another option is to use a drum switch, like this one:
2 hp-7.5 hp Electric Motor Reversing Drum Switch 1 & 3 Phase Position=Maintained 6637433 | eBay
The drum switch can start the motor in either direction. Again, a fused disconnect and an overload device are good additions to the system.

Amazon has a drum switch for $30 that's rated for 63A that might work, but it's not HP rated. (link) A 5HP motor can draw about 100A on startup and that might fry the switch. A better option would be to use a single magnetic starter to start/stop the motor and the Amazon switch to select the direction. But you would need to be careful to only change direction when the motor is off.

What's the HP rating of the motors on the lathes?

Cal

Good point. I was stuck on the 24VDC shown in the diagram. 24VAC contactors, etc., are available and don't require a DC power supply, just a transformer. Automation Direct has carries Fuji Duo Series SC-E contators and they're less money than the ones I was looking at first (which aren't available with 24VAC coils). Looks like a pair of Fuji contactors, the interlock and the overload device can be had for under $100. The transformer adds about another $50.

Cal

thanks all
will look at the lathes again, appreciate all the help