[SwampDonkey]

I have a yakasawa SGDA 01AS drive that outputs 100W @ up to 230V making .87A

I cane across a great deal on 200W motors @100V / 2.7A that would be far easier to install on my machine without modification. Is there any reason I cant run the motors at half the wattage? Would there simply be a drop in torque comparable to the 100W motors? My fearis that they simply wouldnt work at all.

Thanks to you all for your help in this matter.

[mactec54]

SwampDonkey

You are mostly right, it's a very high possibility that they won't run at all, as the drive looks at the encoder & if it is not a match it will not run, If it did run you would most likely burn the drive up in a short time of use

The idea is to never buy the 100w drives as they don't have enough power to do very much with, If this is for a small hobby machine then 200w would be the minimum anyone could use, a 100w may be OK for a 3d printer machine build, but not for a router

[mike_Kilroy]

yep, seems like it should work fine. I dont work with Yaskawa drives but glanced at the manual. Just read your drive manual over and understand it. if you get the 200w motors and put em on the 100w drive, YOU CANNOT BURN THE MOTORS OUT & the drive's peak to continuous current foldback should protect it fine too. and looks like one of the FIRST things you enter when first starting up a system is the encoder resolution.

Quick glance at manual I saw here:
http://www.yaskawa.com/site/dmservo.nsf/link2/MNEN-5CLKGN/$file/TSE-S800-15C.pdf

seems to have parameters to match these up; looked like this series is only increment encoders or dumb absolute encoders and motor is picked from chart in C2 bit 8 and current limits set in CN bits 8&9.

[mactec54]

mike_Kilroy

That is right he won't burn the motors out,(Nobody said it would) but the Drive won't do to well

There is a 50/50 chance that the Drive will accept the larger motor, some of these older drives don't have the encoder recognition set in the software, when you plug the encoder in to the drive, it will auto set the encoder if it is accepted, if it does not accept the larger motor, then there is no way it is going to run it, no matter what parameters you set, this is software controlled

[DeanW]

I was looking for information on this subject because I also have some SGDA 01AS and some 200W motors. I ran across this is the Sigma II FAQ:
>>
When using a matched Servo Pack / Servo Motor combination (eg. SGDH-05xx, SGMGH-05xxxxx) the units are percentage of rated torque.

Sigma II allows (for emergency situations) operation of the Servo Pack / Servo Motor combinations of up two times larger or one-half smaller. This affects the units of the torque monitor by displaying the percentage of rated torque for the lowest rated component. For example:

If an SGDH-05xx and an SGMGH-09xxxxx were combined, the display units would be percentage of rated torque (current) for the SGDH-05xx.

If an SGDH-10xx and an SGMGH-05xxxxx were combined, the display units would be percentage of rated torque (current) for the SGMGH-05xxxxx.
<<

Of course, this FAQ answer is for Sigma II (SGDH,SGDM).

I have been looking to see if Yaskawa docs clarify what parameters and values to set to protect the drives but I have not found any more information on running a larger motor with a smaller drive. I bet the tuning will need to be changed. Also, current limits will need to be set or the drive will alarm. It would be important to use conservative acceleration from the controller to keep the current requirement lower.

The Yaskawa drives seem to be well protected and it seems that they would alarm stop if an overload occurs.
I think that with lots of time tuning and setting parameters, I can run 200W motors using 100W drives. I guess that would be an everlasting " emergency situation"
However, I do not know if the drive current can be limited in a way that keeps an alarm from occurring?

SwampDonkey, are you running the 200W motors on 100W drives? If so, can you share some of the parameters and values you used?

Thanks
Dean

[mactec54]

DeanW

Why there is no information on it is because it is not normally done, what you are saying, that you can use a smaller motor is correct, a larger motor is a no for continuous use

If you wire your 200W motors to the 100W drives, & they run with out a fault, you will be good to go, But the problem is the Drive has to read the Encoder on the motor, the Drive will fault if the Encoder information is incorrect, this is how there Drives are protected, there is no way round this protection

So when you power up the Drive with the Encoder plugged in, The Drive then reads the information on the Encoder, if this is not a Match for the Drive it will not run, there are no Parameters that you can use to change this

The Sigma II Drives also are completely different form the old Sigma Drives, So don't use information for Sigma II Drives for your Drives

[DeanW]

Yes, I quoted the Sigma II FAQ. You are correct, perhaps it does not apply to the Sigma I's.
The drives and motors are Sigma I - SGDA-01AS drives and SGM-02 motors. I believe that these use standard encoder signals instead of the Sigma II serial signal. So, there is no automatic motor identification. I believe that the motor being used is set using the op or the PC software.

As far as running a 200W Sigma II motor on a 100W Sigma II drive, the FAQ says it can be done, so the drives must accept the Encoder info and set appropriate parameters.
I would not want to do that for some kind of production system. I might run a smaller motor on a larger drive if that is what I had available.

These small drives and motors are for powering toys. Perhaps a Printed Circuit Board router / tiny wood carver.
If a drive fries, it is no big deal. I got them for cheap.

I was just wondering if SwampDonkey had some parameters etc. to share.

Thanks.