What power supply do I need? Please help

[Monroe Design]

I am converting a Milltronics Partner IV to EMC2 and need helping figuring out what power supply I need.

The servos are IIC
27lbin
3700 rpm
141 volt
47 pulse amp.

I am going to use A-M-C 30a8 amplifiers they are rated
DC Supply Voltage Range 20-80
DC Bus Over Voltage Limit 86
Maximum Peak Output Current 30amp
Maximum Continuous Output Current 15amp

The power supply I am looking at is an AntekInc model PS-8N80N24 80Vdc 10A, will this be sufficient?

[Al_The_Man]

Those are pretty big motors for those drives, the constant stall torque current rating is around 8 amps.
The power supply is a bit marginal, I think the problem you may see is the drive going into current limit on fast accel/decel moves.
Al.

[Monroe Design]

The drives that originally came with the system are servo dynamics sd1525, these drives were being supplied 72 vdc. What would be an acceptable size power supply to run the amc setup? Correct me If I am wrong but I think that a shunt regulator would be used to keep the drive from going into current limit, I am only going off what I have read on AMC website and through the original machine manual.

[Al_The_Man]

I am just going by personal experience, you could always try the drives if you already have them and up them later if you find you have problems.
I would normally have spec's in 50A8 or 50A20 for these motors, minimum.
If you intend using one power supply for three servo's, for e.g. you may need at least 1.5kva P.S.
The drives have an adjustable current limit that shuts the drive down to protect the motor, these motors may put them in to nuisance operating limit occasionally .
Al.

[Monroe Design]

I am new to the servo thing, I have a stepper driven machine, but have always been confused by the power supplies so I just get what the drive manufacturer suggested. I don't have that luxury with these I guess. I was hoping there was a supply that I could purchase that would be sufficient just to plug the amps in and go.

Is there some sort of tutorial for building your own supply?

I have been thinking about buying new servos as well since the originals are over 20 years old. Are kelinginc's kl34-180-90 servos well suited for the 30a8 amps. The machine is about the same size as a Bridgeport.

[Al_The_Man]

I have roughly the same size motors on some Excello's
I would inspect the brushes and commutators as these are pretty rugged motors.
There are many previous posts here on building power supplies, don't you have the original?
Al.

[Monroe Design]

Yes, I still have the original power supply in working condition. Is there a way to change the output voltage to what i need? i just assumed that I would get the most benefit by getting a power supply rated to the new drives. I appreciate the help the drives are the only thing left in the system that i need to finish the retrofit.

[Al_The_Man]

By rights, to use the motor to their fullest extent, the P.S. should output 160vdc for these motors.
If you total the maximum power required, say 3 x 8 amps at 160vd (125vac) - 60% derating.
1.8Kva minimum supply.
Like I said, if you have everything in place already, see what the results are and up them if needed.
If you do not have the drives, I would look at upping the size a bit.
Al.

[Monroe Design]

Ok, I will try the original power supply and see how it works. One other question, why would there be a transformer between the servo amp and the servo. In the picture the + and - from the card go into the transformer at the bottom and then to the terminal that connects to the servo.

[Monroe Design]

I have been looking at another transformer that would get me closer to the amperage and volts I need to run the new drives as effective as possible. Is this transformer sufficient: http://www.airlinktransformers.com/t...with-leads.asp. I retested the original supply and I am only getting 62 volts at the cap.

[Al_The_Man]

Follow this link back for the explanation of the chokes.
http://www.cnczone.com/forums/showthread.php?t=77532
That transformer should be OK, it will give you ~155vdc with both winding in series.
Al.

[Monroe Design]

Ok, That transformer is definitely too large for the amps I have then. Just as I thought I was figuring it out. One more probably stupid question, can I combine the secondaries like the primaries to gain voltage, it appears if i do so I can come up with pretty close to the voltage I need from the transformer I have, I am too afraid just to try it though.