Clausing lathe VFD question

[OccupantRJ]

Does anyone here have a 5900 series metal lathe with the clutch option who is running a vfd? I am curious how the vfd handles the assumed amperage spike when the clutch is engaged to spin the chuck while the motor is already running.

My unit has worked fine in testing using a static phase converter, but I am now permanently installing the lathe and seeking input relative to how a vfd may react with the clutch usage.

It may be a case of the vfd needing to be upsized, but I have no info relative to this to go on. The motor is 6.5 FLA, 2 hp, and the Teco L510 2 hp vfd is rated at 7 amps.

If you have this lathe type WITH the clutch running on a vfd, I would appreciate your experiences and input.

 

[larry_g]

Do you have an electrical schematic for the machine? It's very likely that the controls are single phase and can be wired on the source power (single) and the VFD used for only controlling the 3 phase motor.

On edit I searched a bit and found this, https://www.hobby-machinist.com/threads/clausing-to-vfd-wiring-help.27400/

Since I'm not a member there I cannot blow up the schematics to see how they did it but they do talk of a 120v for the clutch.

lg
no neat sig line

 

[OccupantRJ]

Larry, it is simply a drum switch for the motor, no other electrical controls. The clutch is a mechanical multi disc unit that stops and/or brakes the spindle when desired. Once the motor is started, the clutch lever is used to start or stop the spindle and chuck. Motor keeps running. The jolt effect the vfd may see when the clutch is used is what my concern is. The vfd has not been purchased yet.

 

[8mpg]

I could be wrong but I doubt it will care. It doesnt know if the motor is a soft start or hard start motor. When I use my bridgeport and drill something and have stalled the spindle, the vfd doesnt react any different.

 

[5ktq]

I can't really see that mattering, the way I see it the surge from the rest of the geartrain getting coupled to the motor is going to be a lot less than the initial inrush when the motor first turns on?

I'd imagine that surge on the motor is less than that when you go from idling to taking a cut...?

 

[rsanter]

I tent to,agree with the opinion that I don’t think the VFD will care.
Most VFDs have programmable,parameters that you should,be able to adjust to compensate

 

[laser3kw]

I tent to,agree with the opinion that I don’t think the VFD will care.
Most VFDs have programmable,parameters that you should,be able to adjust to compensate

I can't really see that mattering, the way I see it the surge from the rest of the geartrain getting coupled to the motor is going to be a lot less than the initial inrush when the motor first turns on?

I'd imagine that surge on the motor is less than that when you go from idling to taking a cut...?

I could be wrong but I doubt it will care. It doesnt know if the motor is a soft start or hard start motor. When I use my bridgeport and drill something and have stalled the spindle, the vfd doesnt react any different.

above is true
the machines I design use a vfd to operate a 7hp motor in a pulse mode. Start and stop several times a minute. No problems with the instantaneous loading. You may get a code, but usually you can tune the parameters to take care of it. There maybe a "torque boost" function you can utilize.

 

[Flail]

Starting the motor from zero is a bigger amp draw then engaging the clutch. When you engage the clutch you are utilizing the inertia of the motor to get the chuck moving.

 

[OccupantRJ]

I felt that the engagement of the clutch MIGHT not be a problem, but it is good to get the experience of others with these units before buying a unit that might be too small for the situation. Worse case is I can use the 2 hp vfd on one of the 1-1/2 hp Bridgeport mills that I will be restoring and keeping for myself, then get something more robust for the lathe.

 

[OccupantRJ]

Thank you all for your input on this. I bought a Teco L510 VFD for driving 2 horsepower. After a little learning curve in setting it up, it is working quite fine. I wired up the controls to the lathe drum switch as I had run a lathe with a drum switch for about the last 30 years, and I like the tactile feedback. I have the vfd set up for 40 to 75 hertz, as the main reason I wanted it was for the 3 phase conversion, and the lathe has it’s own hydraulic speed control.

The clutch on the lathe has no effect on the operation of the vfd, so all is well.

 

[seber]

A big advantage of VFD is the the current draw is limited when used this way. It saves the windings in the motor from that giant inrush both on startup and on engagement. They saved us a lot of money on replacing 10 hp motors even though we rarely used the variable frequency. 44 motors shut down every Saturday night and started on Monday morning in a relatively cold shop. Then started up to 50 time a day for setup purposes. That is pretty hard on a motor. VFD solved the problem.

 

[laser3kw]

I wired up the controls to the lathe drum switch as I had run a lathe with a drum switch for about the last 30 years, and I like the tactile feedback.

I hope you wired the drum switch to the "S" terminals to control the function forward and reverse and didn't use the drum switch to interrupt the vfd output leads to switch the leads to the motor for forward reverse operation.
just pointing this out for future readers.

 

[OccupantRJ]

Good point! Yeah, I wired to the S terminals, gotta read the manual!

 

[OccupantRJ]

Reporting back for others, the lathe has done fine with the Teco L510 vfd. One thing I really like about the Vfd is that when I run the lathe motor, the vfd cooling fan comes on. When I stop the motor, the fan on the vfd stops seconds later.

I actually already had a self start 5 hp rotary phase converter module that I had built at least 15 years ago, but I cannot stand the constant motor hum when I am in the machine shop during quieter moments. No good place to put the idler motor without things getting more involved than I want. I worked in the tool shop at close proximity to a production shop for 30 years and heard 5 spindle Davenport screw machines and such screaming all day, so during retirement, background noise had to go.

I am building a personal Bridgeport mill to use at this time, and after using the lathe the last year, it will definetly be getting a vfd also. This time around I am going to be looking for some dynamic braking for rigid tapping quick reverse.

 

[laser3kw]

check parameter 08-07, that is the fan setting.

08- 07=【0】: Cooling fan runs as the inverter detects temperature rise.
08- 07=【1】: Cooling fan runs while the inverter is running.
08- 07=【2】: Cooling fan runs continuously.
08- 07=【3】: Cooling fan is Disabled.

it is probably set to "1", which is turning it on when the VFD ouputs to run the motor.
If you want a little more quiet, I would set it to "0". That should only turn on the cooling fan IF the unit heats up from use.

L510 manual link

.

 

[930dreamer]

blow up of the schematics.

 

[OccupantRJ]

check parameter 08-07, that is the fan setting.



it is probably set to "1", which is turning it on when the VFD ouputs to run the motor.
If you want a little more quiet, I would set it to "0". That should only turn on the cooling fan IF the unit heats up from use.

L510 manual link

.

Thanks for the input, laser! I may play around with that.