VFD Conversion of a Press?

[bigredmf]

I have a very old hose Crimper/press I am trying to convert to vfd operation.

Motor is 3 phase 3 HP.

In addition to the motor starter there is some 120V control in the panel.

Start and Stop, foot pedal for cycle initiation and limit switches for press position feedback.

The current motor starter is a square D 8536.

I am struggling to figure out how to wire in my Teco FM50 without changing the control scheme.

I considered buying the vfd with the built in Plc but wanted to confirm this system works before a full upgrade to absolute ldt position control.

After all of the successful vfd conversions of old machine tools here I figured Someone might be able to give me some guidance.

Thank you

Red




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[larry_g]

Your in a position where I believe you would be better suited with a rotary phase converter. VFD's work well running motor's but when the machine controls have to be accommodated then things get more complicated. I'm not sure of all the controls on that machine so I will not comment on the feasibility of what you want to do.

Does the pump motor run continuously and the controls run valving, or does the pump motor reverse? Do you have a schematic of this machine?

If the pump motor runs continuously then you may be able to run the pump from the vfd and use a separate 120 volt feed to run the controls and eliminate the control transformer. The motor starter would most likely go away with the VFD and the start stop switch wiring rerouted to the start/stop input of the VFD.

lg
no neat sig line

 

[Willie Makeit]

please also note that the FM50 is only rated up to 1hp.

 

[bigredmf]

This particular version is rated at 3 hp 10.5 amps

Thank you


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[bigredmf]

The problem with the schematic is it for a newer version of the machine that does not use the limit switches.[

Thank you


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[bigredmf]

I can run the motor continuous or toggle it on and off thru the vfd by adding a push button or two

My current thought is to jumper the T1-T3 into both the motor and the starter and just not connect the motor starter output to the motor.

Probably not the correct thing to do but that is why I am here.

Thank you

Red


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[Techie1961]

Do you have more information on the press? Is it purely a hydraulic press with controls on the fluid side i.e. to control the two solenoids with continuous power to the motor? If that is the case, I see very little need for a variable speed control for the motor. You could use it for its ability to create 3P to the motor and some control on start ramp up.

 

[bigredmf]

The vfd is being used so I can run it on single phase. Plus utilizing s soft start of the motor would be nice in my current residential setting.

Indeed there is a double solenoid directional valve that is controlled by a foot pedal and limit switches.

Thank you




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[larry_g]

Looking at the schematic items 47 contacts and 48 would be replaced by the VFD. The 240v would tap off the L1 and L2 as shown to feed the controls transformer. Item 47 , relay, would stay in the circuit for the hold in contacts. The one thing I don't readily see is where to pick up the start/stop for the vfd and if the input for the VFD control is 120 volt or 5 vdc. You may be able to pick a contact set off the item 47 for the start signal to the VFD and tap off the 5vdc for power if necessary.

lg
no neat sig line

 

[454ragtop]

What turns the motor starter on and off? Does the motor run the pump continuously, with the 120 volt transformer running everything else? If that were the case, replace the motor starter with the VFD, leaving the transformer pulling the 230 volt input off the input to the VFD, just like it's wired now. Then just have to figure out how to turn the VFD on and off, depending on what was turning the motor starter on and off.

edit - looks like Larry types faster than me!

 

[Doug Arthurs]

Control circuit is all single phase looks like its stepped down to 120v so this shouldn't be any problem.

 

[Doug Arthurs]

I would create a scenario where you a new switch powers the VFD and then use the old pushbuttons to signal the vfd to energize the motor.

 

[bigredmf]

I very much appreciate all of your helpful responses.

Still stumped with the labeling of MS but will keep digging for a better explanation of wiring of it.

I thought I understood but when I check continuity of the respective contacts some prove out but others not so much.

Thank you

Red


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[928'er]

Volunteer Fire Department?

 

[bigredmf]

Variable Frequency Drive


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