VFD for a Hardinge HLV

maxime.levesque

maxime.levesque

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I have read the threads about VFDs conversions on this forum, and on the practical machinist site, and I was surprised that the need to step up the voltage (from 240v to 550v or 600v) is seldom discussed, my understanding is that some 3 phase motors are designed for 240v, and some motors designed for higher voltage are fine with 240v comming out of the VFD.

My home hobbyist shop only has 1 phase current, 240v and 120v.

My recently aquired HLV (like all HLVs), has 2 windings/circuits for the motor.

The specs for the motor are:

550 volts
circuit 1: 1 hp at 1710 rpm
circuit 2: 0.5 hp at 530 rpm

I was thinking of wiring a VFD to the 1st circuit (1hp at 1710 rpm), see how it goes, and If I find that I don't have enough power at low RPM, then think about adding a second VFD for the second circuit, or something more sophisticated like a "shut everything off and rewire to the vfd to the second circuit" mechanism.

Will this work ?

SHould I used the 2n circuit (0.5 hp) instead ?

Any recommendations on a particular VFD model, features, etc ?


For the coolant pump and power feed motor, I will deal with it later.
 

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Doesn't work that way, a dual voltage motor has different wiring connections depending on the input voltage used, the motor you have is only rated for 550V input. It is a 2 speed motor so might be 4 pole high speed and 12 pole low speed, but both operate at 550V. If one where to use a VFD, the usual method I see is to use a step-up transformer and then a 3 phase VFD, or use a 240V RPC followed by a step-up transformer. Some VFD's can be programmed for 2 different motor paramters, but its gets complex and sometimes the results may not work well. The issue with the HLV is the multiple motors and control system, would need to see the control cabinet/transformer as well as the power feed motor to see if they can operate at lower voltage. Probably simplest solution would be the RPC with a step-up transformer. Voltage is lethal in that voltage range.

You might also consider replacing the main 3 phase motor with a 240VAC (2 Hp) and that could be run off of a VFD, and then use the speed adjust for the RPM range.
 
Agree with Mark- RPC and step up, or change out the motor entirely
 
mksj said:
You might also consider replacing the main 3 phase motor with a 240VAC (2 Hp) and that could be run off of a VFD, and then use the speed adjust for the RPM range.
Click to expand...

I've looked around for used 1hp and 2hp motors, and they are all single phase.

I've read that single phase motors can cause issue on surface finish for a lathe, because the torque is not constant.

Can uneven torque be compensated with a stronger motor ?

I also read that for lighter use (under 3 hp), the difference between 3 phase and single phase is less.
 
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maxime.levesque said:
The specs for the motor are:

550 volts
Click to expand...
Mark has far more experience with VFDs than I , but when I was reading about them before doing my lathe conversion I was impressed with the number of inverters for different ranges and sizes that Hitachi sold. Here is my posting for my PM1440GT conversion. This commonly used inverter will drive motors upto 400VAC.
B2 said:
VFD conversion using solid state electronic components.
Click to expand...


If I understand your situation you have a 3 phase motor that needs 550V AC input. (I assume that this is an induction motor.) You have 220VAC single phase power for the input available.

Inverters can be designed for many situations. There are certainly models which will run off 220 VAC single phase and output higher voltages.
The following is one that Hatachi sells in their SJ-P1 series that will drive up to 1000VAC induction motors. (at least that is how I interpret the spec. ) The motor parameter that is to be set is called Hb 106 at page 12-3-1. (pdf page 160) This is designed for a smaller motor but they have inverters for many larger ones.




However, after you get familiar with these I suggest that you call the Hitachi technical folks (US) and asked them which model you need for the motor and application. You will probably want the 1HP version, but I found them to be helpful so why not ask?

Dave L.
 
In general, with this level/quality of lathe one would want to keep it 3 phase. Surface finish can be worse with single phase, but there are many factors effecting it. I have done a number of single phase to 3 phase motor on lathes due to surface finish issues, and it did resolve the issue, but this is lathe specific. Single phase motors are less reliable, do not tolerate frequent start/stops, and also if too quickly reversed (before the motor speed drops down) they may not reverse properly. Given the complexity of the wiring cabinet and working with high voltage, most people would go with an RPC and a step up transformer to maintain the stock motors and controls. Three phase motors are quite plentiful in the 2-3 Hp range, either eBay or Craigslist or similar, you would want to go with a newer type (VFD rated) motor either TENV or TEFC types. Usually on these types of lathes the speed is controlled through a Reeves type of drive system, so that would be the primary speed control. Without knowing more about your HLV, it is hard to give a specific recommendation, but as mentioned most people take the RPC and step-up transformer approach. The schematic for your lathe shows an auto-transformer with different tap voltages.

A VFD conversion would be more involved, require a new motor (240VAC) and knowledge to integrate it into the lathe, which is not an easy task on this type of lathe. VFD's motor output is wired directly to the motor, so you eliminate all the motor switch gear. Using a VFD with the current motor is not recommended due to the size and motor voltage. If you are running a motor at high voltage 550-600V range, I would only recommend it with a VFD rated motor due to insulation breakdown due to the PWM output of a VFD.

Hardinge HLV-H 220v to 550v?

Hi everyone, just bought an HLV-H from Canada and it is wired for 550v 3 phase. Unfortunately, my shop runs 220v single phase. I've called a ton of places and that seems to be a rare thing to find. Does anyone here know where I can buy a step up transformer that goes from 220-550v? Or can...
www.practicalmachinist.com
 

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My initial thought was to go with a rotary phase converter, then I learned about the need for a step up, and when I started to shop around for a up transformer, I find none that were 550v.
With costs (fusebox + RPC, + step up transformer), a motor swap with a VFD looked simple appealing.

I saw an add for a used 3 phase 2HP motor in my area. Haven't seen the specs, but the owner gave me three numbers for voltage: 208,230,460
I have seen the numbers "208-230/460V" on other motors online, dos that mean the motor can run on either 220v or 460v ?

The RPM of that motor is 1750, which is pretty close to the stock motor in the lathe 1710.

I'm tempted to go with this, it seems like a simple solution.

mksj said:
In general, with this level/quality of lathe one would want to keep it 3 phase. Surface finish can be worse with single phase, but there are many factors effecting it. I have done a number of single phase to 3 phase motor on lathes due to surface finish issues, and it did resolve the issue, but this is lathe specific. Single phase motors are less reliable, do not tolerate frequent start/stops, and also if too quickly reversed (before the motor speed drops down) they may not reverse properly. Given the complexity of the wiring cabinet and working with high voltage, most people would go with an RPC and a step up transformer to maintain the stock motors and controls. Three phase motors are quite plentiful in the 2-3 Hp range, either eBay or Craigslist or similar, you would want to go with a newer type (VFD rated) motor either TENV or TEFC types. Usually on these types of lathes the speed is controlled through a Reeves type of drive system, so that would be the primary speed control. Without knowing more about your HLV, it is hard to give a specific recommendation, but as mentioned most people take the RPC and step-up transformer approach. The schematic for your lathe shows an auto-transformer with different tap voltages.

A VFD conversion would be more involved, require a new motor (240VAC) and knowledge to integrate it into the lathe, which is not an easy task on this type of lathe. VFD's motor output is wired directly to the motor, so you eliminate all the motor switch gear. Using a VFD with the current motor is not recommended due to the size and motor voltage. If you are running a motor at high voltage 550-600V range, I would only recommend it with a VFD rated motor due to insulation breakdown due to the PWM output of a VFD.

Hardinge HLV-H 220v to 550v?

Hi everyone, just bought an HLV-H from Canada and it is wired for 550v 3 phase. Unfortunately, my shop runs 220v single phase. I've called a ton of places and that seems to be a rare thing to find. Does anyone here know where I can buy a step up transformer that goes from 220-550v? Or can...
www.practicalmachinist.com
Click to expand...
 
Hardinge used a presion balanced motor in the HLV's. Mine has a Singer motor that looks like a 10 hp one. Replacing it would be akin to putting a Vokswagon engine in a Ferrari. When running there is zero vibration. I've occasionally seen used motors from parted out lathes, or go with the RPC and a step up transformer.

Greg
 
f350ca said:
Replacing it would be akin to putting a Vokswagon engine in a Ferrari.
Click to expand...

That was my fist thought, just the size and weight of that motor is impressive. I've went back and forth on this decision.

I'll have another look at up transformers.

If I understand correctly, the minimal KVA would be 1.4 x 550 = 770 (where 1.4 is the Amp rating of the motor), so the transformer needs to be at least 1KVA.

Now, most used transformers I am seeing, specify "primary 600v", "secondary 120,240", I gather that this means they are step down transformers.

Apparently transformers are reversible, in some cases, when certain conditions are met, that I don't yet understand.
 
This kind of transformer is abundant in the second hand market, seems like it is intended for "stepping down".
Can it also function as a step up ?
 

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