Renovating a Hardinge HLV-H

[BillTodd]

Here's the first draft of the new control circuit. I have avoided as much 'electronics' as possible (even to the point of using a relay as an inverter) to keep it as a set of simple black boxes.

It works as follows:

By default it powers on to the low speed setting with the Speed Select Relay's nc output engaging the 2ML contactor connecting the low speed windings to the VFD.

If the Speed Change Lever is moved left to the Slow position. A RUN signal is supplied to the VFD via the Speed Select relay and R1/C1 (more on these later). The VFD's 0Hz contact will close, switching the output of the Inverter relay to open. The VFD will ramp up the motor to full speed 480rpm (50Hz) in a few seconds.

Now If the Speed Change Lever is moved right to the Fast position. The Speed Select relay's no output is open so the RUN signal drops to OFF and the VFD ramps down to 0Hz (Stopped). When it reaches 0Hz the VFD's output contacts open forcing the Inverter relay's output to 24v. The 24v 0hz signal is used to change and latch the Speed Select relay to High speed. As the relay changes speed, R2 is taken to 24v, charging C2 in about a hundred milliseconds (to give time for the contactors to settle) and generating a new RUN signal to the VFD. (R4 discharges C1 via R1 ready for the next speed change)


If the Speed Change lever is then switched back to the Slow position, when the 24v 0Hz signal is generated, it is applied to R3 which disables the Speed Select relay's coil so switching it back to Slow.

If the Speed Change lever is centred (STOP) then the RUN signal is removed and the brake is applied. The previously selected speed is retained by the Speed Select relay.

[Jonathan P]

Looks good, My HLV is # 461 and thought it would be while before I saw an older one. I was too looking at swapping out to an Inverter, at the minute, I have it rigged so that the ctrl is supplied direct of 240 mains, (bypassing the transformer) and I engage the slow or high run relay’s before I tell the inverter to ramp up. (Not ideal – but ok temporary) I might inquire as to how Cyclematic lathes do their speed control. Do we know how the new Hardinges work ? – be good to see a new Schematic and even more interesting would be the New HLV that has just come out, with the servo leadscrew. In my case I have only just ripped out and restored the wiring to original and everything works fine so I may try to keep it original. Quick question,, with regards to the brake, you are still retaining the mechanical brake solenoid. This is the way I would be doing it, but thinking about it there may be some merit in using the inverter to do the braking, what are your thoughts on that? The auto transformer you are using is single phase, are you doing the same as me and feeding the inverter with 400V single phase ? and not running it at full capacity ? I should really get some pictures of mine on this forum.... I have just got to the primer & paint stage, (lotts of dammage to my carrige gears + rebuilding the carrige feed motor + revising its electronics have taken a lot of time) Best Jon P