Rewiring 13x30 monarch model 61 from 480V to 240V

[mksj]

Kind of late to this discussion, but I agree with Dave. Most VFD drives above 5Hp are rated for three phase input, almost all can be used with single phase input in a derated mode. You need to go back to the manufactures specifications for derating, not only for running in for single phase, put all derating applied to the application use. Invertek does offer single phase input VFD's up to 10 Hp, but they are quite expensive, and my limited use with them is that they are very limited as to inputs and programming unless you get into their higher end more expensive models. If running in open loop SLV I normally would recommend the Hitach WJ200, Yaskawa GA500, Teco E510, Fuji also has a wide range of VFD models that are less expensive then the Invertek. Lapond, HY, or whatever generic VFD's do not cut it and I do not waste my time with them.

You basically would eliminate all the current electrical cabinets components as they would not be applicable to use with a VFD. You also need some form of basic run controls to interact with the VFD with safety interlocks, this could be wither push button run controls run as 3 wire control, or 2 wire control with a basic relay control system.

If you want a plug and play system without the VFD controls, then I would go with a Phase Perfect which they have a simple basic 7.5 Hp version which is priced in the same range as a new RPC, or make your own RPC. Problem with the latter is you would need a 15Hp idler motor, and a significantly larger power service. In either case when rewiring from 480 to 240VAC you would need to change your fusing/overload devices. Cost of a VFD system would be equal or most likely greater than the cost of the Phase Perfect PTS007. If you are running multiple 3 phase machines and just need a 3 phase power source, than I would recommend the Phase Perfect.

Phase Perfect single to three phase power converter

www.phasetechnologies.com

 

[sledder]

I purchased this Invertek VFD rated for 5hp for my Monarch 7.5 hp.

ODE-3-320153-1042 | Industrial IP20, 4kW, 230V, 1-ph in, 230V, 3-ph out

Details4 kW (5 HP), 15.3 A, 200-240 V, 1-3PHIP20 Variable Frequency DriveInput RatingsSupply Voltage200-240 VInput Phases1Supply Current Continuous29.2 ASupply Fuse or MCB (Type B)40 AOutput RatingsMotor Output Rating4 kW (5 HP)Output Voltage0 – Supply VoltageOutput Current15.3 ACable...

www.invertek.com.au

 

[Jdub63]

I purchased this Invertek VFD rated for 5hp for my Monarch 7.5 hp.

ODE-3-320153-1042 | Industrial IP20, 4kW, 230V, 1-ph in, 230V, 3-ph out

Details4 kW (5 HP), 15.3 A, 200-240 V, 1-3PHIP20 Variable Frequency DriveInput RatingsSupply Voltage200-240 VInput Phases1Supply Current Continuous29.2 ASupply Fuse or MCB (Type B)40 AOutput RatingsMotor Output Rating4 kW (5 HP)Output Voltage0 – Supply VoltageOutput Current15.3 ACable...

www.invertek.com.au

That seems backwards, you're running a 7.5HP spindle motor with a 5 HP VFD?? Does your spindle motor draw less than 15.3 FLA 3 Phase? That looks like the rating for the VFD.

 

[sledder]

It works great and I have not had any issues with it all. I found one on Ebay for $600, you can't beat that price. Max amps are 15. The only issue with the 5 hp. inverter on a 7.5 hp. motor is if the spindle RPM is set fairly high and if you clutch it in rather quickly it will trip out, and then you need to turn it off and turn back on and it's ready to go again.

 

[Drdetroit1985]

I am looking at rewiring the motor on my Monarch model 61 13x30 lathe from 480V to 240V, and there is no motor tag on the motor or anywhere inside the motor access door. Luckily, the wires were labeled though (maybe by the last electrician that touched the motor ... as you can see in one of the pictures below, a blue service tag is attached to the motor).

You can see in one of my pictures below my notes on how the motor is connected to the lathe electronics enclosure. The connections appear to math the 'High Voltage' diagram here:

https://control.com/uploads/articles/image2_motors.jpg

To rewire the motor itself is the easy part for me; I can just rewire it per the 'Low Voltage' diagram linked above, right?

Now, to rewire the cabinet and the square D safety switch (a picture of both is linked below) is where I am stuck.

Inside the cabinet at the bottom there is a control transformer with a red tag, it is currently wired for 480V out as you can see by the jumper between the screws at the top. That's simple enough, I can just jumper it per the diagram on the red tag for 240V. My question is, what else do I need to do in this lower cabinet and also at the square D safety switch at the top?

I will of course be running the machine from 240V single phase at the wall via a VFD to 3 phase 240V.

A bunch of pictures here:

https://imgur.com/a/eQGJGK7

I know this post is old but , anytime you switch voltage from 480 to 240 the motor starter coils must be replaced with 240 volt coils or the contractor will not pull in , 480 volt coils do not like 240 volt .I have had to change these out on several occasions not to mention the motor starter heaters , must be sized to the voltage name plate rating or look up voltage rating in 3 phase motor section of a electrical code book article 430 ! How do I know this ? Master electrician for 25 years , you probably have all of this going by now though but is good info going forward !