What dc voltage to use on rutex R90H drive

The existing power supply of my 1980 Kasuga cnc milling machine is 100 volt dc. It is servo driven(West amp drive). What would be the recommended Voltage if R990H is used.

I believe 100 volt at 20 amps is the limit for this drive.

So does this mean there will be no problem with drive faulting due to motor deceleration even if my power supply voltage is 100 vdc. Thanks for the help.

Are you just replacing the drives or both control and drives? As the Westamps are usually analogue +-10vdc , the Rutex are I believe step and direction only.
Al

Gentlemen,

As far as your Kasuga mill is concerned, you may find that 90 vdc will give you sufficient speed. I would bet on it. Otherwise, you might need to consider the R90H drive.

Tom Eldredge,
Rutex, LLC

Yes, both drives and control will be replaced. Using another tap on the transformer power supply yielded 94 vdc, so I'll go ahead use R990H.

I have now the R90H drives. Decided on the 200 volt/40 amp drives because according to the people who knows running R990H on over 90 vdc have only 10% margin of getting ruined from overvoltage.
Also have the E2 single-ended encoders, ttl or open collector type from USdigital.
I've read somewhere along this Forum that such type of encoder will have problem with noise especially in industrial environment. Is this true?

Bob, yes it is very true. Don't even waste your time wiring up single ended encoders. Do it right the first time and you'll save a lot of frustration.

Thanks I----EPP,
I waited for your confirmation, now I hope USdigital will accept these for return.

Yep I made the mistake of using single ended encoders. Now my Rutex cards have to ride along with the gantry. In some ways it is better because you dont have to run control wires along the power chain. However it is a bit messey having the cards on the ganty.
Rutex has a product that will alow you to use single end encoders with longer lenths of cable.

Bob,

If they don't want to take them back just order the PC45 (http://www.usdigital.com/products/pc45/) It plugs directly into the E2 encoder and gives you differential output.

Andreas

Thank you guys, Without your valuable help I would have gone nuts this time. Rutex drive cards riding on the Gantry is funny and clever. By the way, does the PC45 meant PC4 or PC5 cable driver that convert single ended output to differential output?

Bob F.

Ooops, sorry. Yes, it is the PC4 or PC5, not PC45. Depending on what pin output you want. If you call US Digital, they can hook you up with the right stuff. I have E5 encoders and I needed their EA-D8 for the same reason, but that is another story.

USdigital took them back without restocking cost. I ordered the E5D encoders, this time its differential output and acccording to Rutex, length of encoder wire could be any length desired and not picky on the kind of wire.

Hey Bob, Just outa interest, how much did the encoders cost you?

Cost of encoder is $52 and a 10 ft cable with corresponding plug is $24.

I am retro fitting a large heavy duty lathe (14') with R90H drives, using Mach3 to drive them ...

The Z-axis motor is rated 215VDC 35A continuous and the X-axis motor 200VDC 29A continuous. Has anyone used the R90H/R2020 with motors as large as these? I am supplying 180VDC to both the drives.

Has anyone worked with motors as large as these? I'd like to know how you tackled the job...

The Z-axis of my machine is working OK ...I am now working on getting the X-axis working OK.

This lathe also has a 8-station tool turret for which I have written a Mach3 macro that drives a proprietory microcontroller-based card to control the tool turret. I would like to contact anyone who has worked with driving tool turrets too ...

TC Tech,

Those are some pretty large motors. The R90H drives should be able to drive them at the lower voltage if you are able to make adequate provision for the "braking".

We have a motor and drive matching document on the Rutex.com web site under the R2000 products. It generally applies to the R90H as well. Your motor must have a minimum of .015 ohms resistance for each volt applied to the motor. In other words, for a 180 vdc VM, your motor must provide a minimum of 2.7 ohms. I'm sure these big motors do not. In fact, I'll bet that their armature resistance is less than or close to .3 ohms. Therefore, you should put a 2.5 ohm resistor in series with your motor. Note also that the wattage of the resistor will need to be very high...around 2000 watts if your motor . These types of resistors may be available through manufacturers of VFD drives. They use them for braking also, but the ones I am familiar with are rated a little higher than 2.5 ohms resistance, (25 ohms) so I'm not sure where to tell you to get such a large resistor.

Please read the above referenced document to get an understanding of how this configuration will be expected to perform, what losses to expect, etc.

Tom Eldredge
Rutex LLC