servo motor help

[max_imum2000]

i need to know what are the diff between a servo amp and a servo controller, i have someone selling a motor that comes with both , so i am not sure what are these, i though they were the same thing.

also if the cont current is 7amp and my transformer can deliver 11amp will that be ok to use ?, i mean the peak current can reach 20amp or so in the motor for small period of time, will the power supply will be able to stand this ? if not any other solution rather than a new transformer ?

Thanks for all ur help

[Al_The_Man]

Originally Posted by max_imum2000 i need to know what are the diff between a servo amp and a servo controller,

About $600
Seriously, they are often used to indicate the same thing, although you can get servo amplifiers that are strictly non inteligent devices, they do not have any processor on board.
There is also servo controllers that have intelligence and not only have the servo amp, but have logic control on board, these are often used in stand-alone applications, but some times can be integrated with other systems, You would have to research the specs. for individual units to get a definitve answer.
The peak current of a motor is usually the maxumum current that the motor should be subjected to before damge or de-magnetization occurs, it rarely reaches that in well designed system.
Al.

[max_imum2000]

thanks al, i can always depend on the forum and great guys here for answers
well the amp is
BREGENHORN-BUTOW
TYPE TRL150/15
D-79108 FREIBURG SER# S035A0045

its german made, and i dont have any other info about it
anyone knows if it can accept step and dir, or i will have to dump it

[KTP]

Nooo! don't dump it....wait just a few days for my step/dir to analog PID controller boards to arrive. :-) I am doing an initial run of 100, and they will be very cheap (probably $49).

[max_imum2000]

That will be great, will there be pcb avilable and kits and so on ?
if you want any testers , let me know

[KTP]

I have already gone through a lot of testing. These will be the third redesign of the board...this time I added all screw terminal connectors, an option for controlling Fanuc brushless motors that don't have hall sensors, and a few other improvements. I am working on the data sheet and example wiring diagrams now, but the tuning/setup software (requires just a PC with a standard serial port) works great. You can set and store features like step multiply, max error, and of course the PID parameters, and you can view the step impulse error as a graph. On brushless motors you can graph the running error, and use that to mimimize torque ripple with the cheaper trapezoidal amplifiers.

As for kits...I was planning on providing tested, completely populated and soldered boards for $49. The board uses all smt parts (except connectors) and you really would need a microscope to aid in assembly and inspection. I did switch from 0603 to 0805 caps to speed assembly, but that is not going to help much. Also, the board uses a cpld to condition the encoder signals (with digital filtering of any noise), so a kit would have to provide some way of programming that.

Over the next few days I will be changing out the Gecko drives on my 7000lb Shizuoka milling machine to AMC or copley drives (bought on ebay for less than $40 each!) and these step/dir to analog controllers. I will have a Fanuc 5 DC servo motor on the Z axis, a Fanuc 0 DC servo motor on the Y axis, and a Fanuc 5 brushless servo on the X axis. This should provide a nice additional testbed for the controller.

Rick

[NC Cams]

"...if the cont current is 7amp and my transformer can deliver 11amp will that be ok to use ?, i mean the peak current can reach 20amp or so in the motor for small period of time, will the power supply will be able to stand this ?..."

It depends. What is the duty cycle rating of the 11 amp p/s??? The rated duty cycle at peak current of your p/s really needs to be known to answer your question..

Assuming there is no current foldback/limiting in your amp/controller, several things could happen and the results are usually time dependant if you get to 20 amp surges.

As the current limit of the transformer is reached, it can/will start to heat up. This can cause a reduction in efficiency and/or winding damage/shorting.

You'll also find that output voltage will drop as the system is designed for output power (kva). Thus, simply put, if you have a transformer that can put out 10 amps at 100 volts, that is 1000watts (1kva). (oversimplified), at 15 amps (if the ciruit can pass that much overcurrent), you might see something akin to 66 volt output (more or less).

Expect to see speed reductions at higher current draws due to voltage foldback - power will diminish. Motor and/or transformer overheating at higher current draws that meet or exceed the rated current of the p/s.