Monarch 10 EE

[John_Dennis]

I am looking at a Monarch lathe it has a swing of 12.5 I think it is a 10 EE from reading other post.

It has a huge solid state control box mounted on the wall that apparently replaces the original tube controller. I believe that this machine probably has a larger motor than I can run in my shop. I would have to replace the motor with a 2 horse 3ph motor with VFD.

Has anyone done this conversion? how hard was it and are you satisfied with how it works?

Thanks

John

 

[Cal Haines]

I am looking at a Monarch lathe it has a swing of 12.5 I think it is a 10 EE from reading other post.

It has a huge solid state control box mounted on the wall that apparently replaces the original tube controller. I believe that this machine probably has a larger motor than I can run in my shop. I would have to replace the motor with a 2 horse 3ph motor with VFD.

Has anyone done this conversion? how hard was it and are you satisfied with how it works?

Thanks

John

John,

You won't get anywhere near the same performance, particularly on the low end, with a VFD setup. Plus it's a huge amount to work to do it right. As long as you have a 30 amp, 240 Volt circuit in your shop, you should be able to run any 10EE drive out there.

Cal

 

[John_Dennis]

John,

You won't get anywhere near the same performance, particularly on the low end, with a VFD setup. Plus it's a huge amount to work to do it right. As long as you have a 30 amp, 240 Volt circuit in your shop, you should be able to run any 10EE drive out there.

Cal

The current owner thinks the motor is a 3 phase 7 horse motor. The motor alone might draw more than 30 amps plus a rotary phase converter that I don't own yet.

 

[AlanR]

The current owner thinks the motor is a 3 phase 7 horse motor. The motor alone might draw more than 30 amps plus a rotary phase converter that I don't own yet.

I get about 22 Amps max for that. Once the convertor is spinning (start it first) its own draw isn't much.

 

[Walt]

The current owner thinks the motor is a 3 phase 7 horse motor. The motor alone might draw more than 30 amps plus a rotary phase converter that I don't own yet.

The cost of a rotary phase converter and wiring for 30 amp service will be trivial compared to the cost and effort of putting in a different drive on a 10EE, and getting good performance out of it.

Drive conversion apparently is a major undertaking even for guys with decades of experience with electric motors. There is another machinist website with a Monarch forum you can find easily with a Google search. If you are serious about pursuing a conversion, do yourself a favor and read some of the hundreds of pages of posts on the topic. The can of worms you are looking at is vast.

Walt

 

[old_dave]

The current owner thinks the motor is a 3 phase 7 horse motor. The motor alone might draw more than 30 amps plus a rotary phase converter that I don't own yet.

Monarch Lathes uses a 7 1/2 H.P. three phase motor with VFD (along with essentially the same gear reduction box that they used with the earlier D.C. motor drives) on the new 10EE's they've been building as well as doing this as a retro-fit on 10EE rebuilds. The wall mounted cabinet doesn't sound like their work though. A picture would help. In any case it sounds like this 10EE does not have the DC motor drive.

David

 

[Cal Haines]

The current owner thinks the motor is a 3 phase 7 horse motor. The motor alone might draw more than 30 amps plus a rotary phase converter that I don't own yet.

Unless it's a pretty new lathe (built since 1980) the original spindle motor was probably a 3 HP Reliance DC motor. (Certainly all of the tube-drive machines were that way.) IIRC, some of the later solid-state DC drives had a 5 HP DC motor as an option. A 7 HP, 3-phase AC motor is probably a refit. A 2 HP AC motor with a VFD will be woefully underpowered; 5 HP is marginal. Some guys are happy with a 7.5 HP 3-phase motor, coupled to the original back-gear unit, but nobody claims that their VFD actually performs better than the original 3 HP DC drives.

Get information on the current spindle motor and drive and we'll see what you need to power it. If it currently has a 3-phase spindle motor, the box on the wall is probably a VFD. You need to get the make, model and power requirements (which should be on a tag somewhere on the box or the module inside) of the existing controller. Depending on the VFD (if that's what it is) it may be able to run from single phase. You might need to upgrade the shop circuit to 60 amps to handle it, but that shouldn't be a big deal.

What electrical power do you have available in your shop?

Cal

 

[old_dave]

Unless it's a pretty new lathe (built since 1980) the original spindle motor was probably a 3 HP Reliance DC motor. (Certainly all of the tube-drive machines were that way.) IIRC, some of the later solid-state DC drives had a 5 HP DC motor as an option. A 7 HP, 3-phase AC motor is probably a refit. A 2 HP AC motor with a VFD will be woefully underpowered; 5 HP is marginal. Some guys are happy with a 7.5 HP 3-phase motor, coupled to the original back-gear unit, but nobody claims that their VFD actually performs better than the original 3 HP DC drives.

Get information on the current spindle motor and drive and we'll see what you need to power it. If it currently has a 3-phase spindle motor, the box on the wall is probably a VFD. You need to get the make, model and power requirements (which should be on a tag somewhere on the box or the module inside) of the existing controller. Depending on the VFD (if that's what it is) it may be able to run from single phase. You might need to upgrade the shop circuit to 60 amps to handle it, but that shouldn't be a big deal.

What electrical power do you have available in your shop?

Cal

Just dug up a history of the 10EE (originally posted on another forum back in May, 2002) It says Monarch started using the "module box" drive and the 5 HP D.C. motor in 1960. I know Cal knows this but in case anyone else doesn't, the "module box" drive used a combination of solid state devices (diodes) and three thyratron rectifier tubes. The diodes are in a black box, literally, called the module box.

The important point here is, as Cal says, the more definite information you can provide about the motor and controller on this machine, the better the subject matter experts here (not really including myself as one) ail be able to help you.
David

 

[Cal Haines]

Just dug up a history of the 10EE (originally posted on another forum back in May, 2002) It says Monarch started using the "module box" drive and the 5 HP D.C. motor in 1960. ...

That's correct. My mistake (that's what I get for going from memory). The drive is usually referred to as the "modular" drive.

Cal

 

[compressorguy]

I get about 22 Amps max for that. Once the convertor is spinning (start it first) its own draw isn't much.

In a perfect world it works out to about 25.4 amps. Inrush will be about twice that. A standard residential 30 amp breaker might trip at that. I run my 7.5HP single phase compressor on a 40 amp circuit with no issue. FL amps on that motor are 29.0 (single phase isn't as efficient as three phase)

Gary H