GE DC Drive

It works! The DC drive sold through this BB is running my Reliance 3hp DC motor and I had a message that Julian has had his GE 5hp motor running. This was a "learning experience" and part of that experience was a $185 phone call to GE Customer Service to learn something that was in a newer version of the operating manual but not in my copy: this drive requires a tachometer for speed feedback if it is to operate in field weakening mode. So I had to add a tach generator to the "off" end of the motor shaft.

Some general comments about this conversion: this drive is very sophisticated and the manual does not supply all the information required to program for different uses. We were very fortunate that the drive was originally configured for a for/rev, field weakening, regenerative braking spindle drive with analog tach feedback. But the speed control was a 0-10v signal from the machine controller. There was no information anywhere about converting the drive to manual speed control with an external potentiometer, nor was it very clear how to install the external for/rev switches. Julian obtained this information.

Some of the changes required to program this controller for a different motor were in the start-up guide and were simply changes in jumper locations in various circuit cards. Other changes required the use of either a hand-held controller or special software installed on a computer. Some of the parameter changes were in the manual, others had to obtained from GE. I asked the GE engineer if he could simply input my motor parameters into his software and print out my drive parameter list. He was puzzled by the request and said that he did not have that capability and didn't even know who did. The drive was programmed for its intended purpose at the factory and was apparently not expected to be significantly changed in the field. GE does not publish all the parameters, their values, and the engineering decisions required to program the drive. The lesson: drives of this this type may not be field re-programmable, and will definitely require access to either a hand-held programmer or computer software. You cannot just look at the wiring diagram, add a 5K pot and some switches to a terminal board.

Do I like the drive: you betchum! It is connected temporarily and the motor is sitting on the welding bench, but it has been in the lathe and running the spindle. Low speed torque is incredible, acceleration and deceleration are impressive. As part of this project I will compare it with my working WIaD and report to the BB.

One other detail: the drive operates quite well on my 3hp 3ph rotary converter, but it has not yet been loaded by making a cut. The lathe is still apart for cleaning, maintenance, and repair.

It's been my experience that the information is in the manual but because of the way it's laid out and presented, you really have to dig for it.

In other words, some parameters are "linked" but, in the documentation, they are not always grouped together or cross-referanced.

Accessing it is pretty easy using a PC and the DC-300 software or just a terminal program. Like anything else, you just have to get used to it. The interface card would be nice but it's not necessary.

I have one connected to a 3hp large frame Reliant (outside the lathe) for testing. I have all the functions (forward/rev/braking) but no field weaking since I have yet to connect a tach. I'm currently running it in CEMF mode. It looks very promising, though.

Anybody out there have a motor tach that's just cluttering up their space?

Doug

PS: Be careful setting up the braking. I made the mistake of setting mine for 1/2 second braking instead of 2 seconds. It's easy to do given the scaling format of the parameter. It blew the aramature fuse. These drives have all the bells and whistles + copious amounts of safety, too!

Doug, I loaned Julian a tach/gen to try on his. Have not heard anything back from him. You might check with him to see if it's working.

Howard

I bought one of the drives from Julian also. I'd be grateful if you could share the parameters you learned from GE and what connections you made on the DC300 drive. Also, how did you wire up the motor since the drive has Field and armature terminals but no shunt terminals on it for the 3hp shunt wound motor.
Steve

Doug: I deliberately cast a rather wide net in my comments on the drive. This was to keep someone else from making the assumption that this would be an easy conversion. I specifically had in mind 2 parameters (GE calls them software jumpers in the manual) adr000 and adr001. Adr000 is REFJP: reference jumper and controls which input the drive accepts for speed control. The value of 00512 was programmed into my drive and this was for a 0-10v voltage follower which is shown on the elementary drawing. Our application requires a manual speed reference and the associated value for adr000 is 00000. I have not found this info in the manual. Similarly for adr001: FDBJP (feedback jumper). My value was set at 00003 which is analog tachometer. The other values are 00000 (CEMF), 00001 (digital tach), and 00004 (quad-trac pulse tach). Julian sent me one of these values, and I got the other two from GE. The engineer said that they do not provide all of the information required to fully program the drive. This is the background for my cautionary statement that an individual may not be able to do this conversion on his own.

One other detail, our drives have the Process Interface Board which accepts the tachometer inputs. Should someone purchase one of these drives on the secondary market without this board, he would be unable to run a Monarch to full speed because he would be restricted to CEMF feedback and its limit of being able to control the motor only up to base speed.

I was also thinking that other drives may also present similar problems.

Speaking of failing to find, and failing to understand: can you provide some info on using the terminal mode. I do not understand "Capture On (F1) and Capture Off (F2). Also, Julian sent me the keystrokes to read and write to an address. Where did that info come from? Is there some basic knowledge of the terminal mode that I do not have? I'll cheerfully admit that I have had some rather tough going trying to understand this drive. But it's running and that's what counts.

Carl

"Also, how did you wire up the motor since the drive has Field and armature terminals but no shunt terminals on it for the 3hp shunt wound motor."

On the drive, "Field" implicitly refers to the shunt field of the motor, F1 and F2.

Some motors are compund wound, and these have A1, A2, F1, F2, S1 and S2.

S1 and S2 are is the series field, which must always have the same polarity as the shunt field, although it is within the armature circuit, so there is no way to ensure this requirement short of placing the series field within a diode bridge.

Older motors are not compound wound, and have only A1, A2, F1 and F2.

Some motors, particularly the later GEs, have 115/230 fields, although the nameplate says the field is 115 only.

My 5 HP GE has eight wires, and the four shunt field wires are connected in parallel within the motor's connection box (AKA, "pecker head").

The GE drive does not use the series field and these leads are taped off. I will eventually compare the performance of the motor using the WIaD and GE drives. I was going to ask the GE engineer about using the series field inside a bridge per Peter's idea, but didn't for several reasons. I don't know if I will try it as an experiment. Peter, any idea if that could conceivably damage internal components of the drive?

Carl

"Peter, any idea if that could conceivably damage internal components of the drive?"

I don't know, specifically, about the GE drive, but the Imperial and Joliet drives both included the series field within a bridge.

And at least the Joliet drive package, which may have included an off-the-shelf dc drive, perhaps even a GE dc drive, also included tachometer feedback, as does the GE drive currently under discussion, in field-weakening mode.

It is best to use the series field, where available and possible, as it improves the performance of the machine under heavily loaded conditions.

It is possible that the GE drive presently under discussion uses tachometer feedback to detect a motor runaway condition, which can also be detected, although with less precision, using a field loss relay, or a shunt resistance.

Peter: I might as well try the series field. I'll let the group know what happens, but this won't be soon.

The GE drive has a parameter for speed limit which senses the tach gen output in tach feedback mode and counter emf in that feedback mode.

Carl

Interested to hear follow up and feedback from any 10EE users running a DC300 drive.
Are you happy with the drive's performace in day to day use?
Does it equal or exceed the reliabilty and performance of a 10EE with the factory Modular drive?

Looking at the dates of the prior messages: I've been running my DC300 for a bit more than 8 years with absolutely no problems. Unfortunately I cannot compare it with a modular drive as mine is a WiaD. I am using my original parameter set which could probably be tuned a little better, but I am completely happy.

Carl

Hi Carl
Thanks for responding, I have read many posts about drive conversions, but not much follow up regarding the long term performance after the installation.

Does your DC300 machine retain normal 10EE features like reversing, braking and 4000rpm spindle speed?
Can you make heavy cuts without the drive bogging down?
What aspects of the lathe's performance feel would be improved if the parameters were tuned better?

Thanks
Steve

Steve AKA Colt45 clear out your PM's and or send me a regular email (or add your email to your profile) - I got your message but cant send the response.

Paul