Leblond Regal voltage change

Hello guys and gals - new member here. I thought I might jump in and use some of the collective expertise if you don't mind.......

I am looking a 15" x 30" Leblond Regal 11C series servo shift machine. The machine cabinet shows that its wired for 460V. I talked to the nice fellows at Leblond and they stated that everything "should" be able to be switched over to 230V. I found this post - http://www.practicalmachinist.com/vb/1312072-post13.html - that gives a nice layout on how to do it, but no follow up stating if it worked. Does anyone have any first hand input on this process they would like to share with me?

Also, thoughts on Leblond/Servo shift specific problems to look out for when I inspect this machine? How about thoughts on ex-tech school machines?

Thanks in advance.

Switching it over is one option, a step up transformer is another. You can probably find a suitable sized surplus step up transformer for less than all the bits and pieces required to convert it to low voltage. I have a mill at the house that has high voltage VFDs and could not be swapped over to run on my phase converter without spending a several hundred dollars on new VFDs. I found a 15KVA transformer for $100 and had it hooked up and running in a couple of hours.

Not sure what size motor you have. Get with an electrician or ask the guys over at the converter/VFD forum if you need help figuring that. The converter/VFD guys can also be of enormous help if you decided to swap it over to low voltage, instead.

The last line of the linked instructions is usually the most difficult. The reason for this is that the magnetic starter is almost always as old as the machine. "Replacing the overloads" sounds easy - that is until you try and find a source of parts replacements for antique electrical equipment.

My experience with such is you go to the industrial electrical supply, give them the make and model of the magnetic starter, and more times as not you will either get a blank stare, or the sharper ones will mention the last time they stocked parts for THAT was way before they came to work there.

J.O.

Thanks for the input fella's. To clarify more - this machine should be 7.5hp and manufactured in 1979. If my math was right, I need about a 7KVA transformer. I didn't find any cheap with a quick search of the net. I may take the suggestion and copy my original post to the VFD/converter section to see if I can get anymore info.

Check Ebay, local industrial surplus shops and see if you can find a local industrial electrician. You want to buy a surplus or used transformer, not a new one.

I need about a 7KVA transformer

Click to expand...

Acme Transformer, where I bought mine new, said twice the KVA compared to HP when using as step up.

My 3KVA has run this 1 1/2HP for about ten years.

J.O.

I was thinking 15KVA sounded more like it, John.

Well the machine is sitting on my garage floor now. Its a 1979 model so I am fairly confident that I can find the needed overload heaters. Thanks for the advice. Hopefully in a few weeks I will have this guy in place and hooked up and I will let you know how it works out.

I found the two (one for the spindle motor and one for the hydraulic motor) needed thermal relays on eBay and they are on the way. They are the bi-metal resettable type with some adjustment, but not enough for double the amps. The 7.5 hp Toshiba motor specs out 7 RMS amps and the thermal overload relay on the reversing contactor for the motor was set to just above 6 amps. So doubling that for 240V would give me 12-14 amps and the max setting on the relay is 8. The replacement is 13-18. Same situation on the hydraulic motor. I will let you guys know how it works out when they show up.

If the overloads are not longer available, what's the possibility of installing fuses?

I am thinking a single phase situation then pops up, but couldn't a clever and determined person have three small relays, one on each leg, and when any one fuse fails, the series-connected relays open the three-wire 'stop' circuit?

Of course, by the time the enclosure is purchased, the fuseblock, fuses, relays, labor, etc, the cost approaches a used motor starter.



I think this would be filed under Last Resort, when a VFD isn't an option.

That could be an option for a handy sparky, but luckily for me the ones I needed are still available. They are a direct replacement so no rewire or remounting of components. I may have been able to use the originals, but since the Leblond does not use a clutch, I figured the upper RPM spindle speeds would trip the relay. I will be using a RPC to power this, a VFD with the low amp start would be nice but pricey for the motor size.

The two new thermal overloads arrived and are installed. Switched the leads for the two motors from 460V to 230V. Didn't touch the main fuses but plan on replacing them. Ran temp power from my homemade 10hp RPC and fired it up. Runs great! Trips the idler breaker at 1800 RPM, but it is only 30 amps since the feeder wire is 10 gauge. Just placed my order for an American Rotary panel and will be upgrading the wire and breaker. Now I just need to tool it up!

If anybody else runs across this in the future here are the two thermal overload relays I used (Telemecanique switchgear);

Telemecanique LR1-D09308A65 - pump motor (set to 3 amps)
Telemecanique LR1-D16321A65 - spindle motor (set to 13 amps)

The process is this, use at your own risk;

*MAKE SURE THERE IS NO POWER TO THE MACHINE*

1. Open spindle motor plate and switch leads as shown under connection plate.
2. Pull the cabinet off the back of the machine and do the same for the pump motor. There are two leads marked "J", they are for thermal protection and don't need to be switched.
3. Switch the three large main fuses out for twice the amperage. There are three smaller fuses in the cabinet. Don't switch these. These are protecting things on the 120V feed from the transformer.
4. Swap out transformer input. The directions are on the transformer. You should need to make a small jumper for this like the existing one.

Thanks for the info, I know this is an old thread, but do you happen to have the wiring diagram for the servo motor, I have no tag showing what wires to connect for 220v, they are currently at 480V.

Thanks,
Bob