Brushed servo drive replacement

[motordude]

I need advice on which unit to use when replacing the Simoreg servo drives on my machining centres (type and manufacturer. I want to kep the servo motors.
The servo motor has a 20V, DC/1000 RPM Tach that connects to the Simoreg and a resolver that goes to the controller. The Simoreg get a +-10V signal from the controller.

Number of feed axis: 3
Rated supply voltage (50/60Hz): 3-phase 165V
Rated DC voltage: 3x200V
Rated DC current:3x25A
Peak current limit (200ms):3x50A

Thanks!

Best regards
John

[Al_The_Man]

John, Is that three seperate drives or a combined unit? The 165 v three phase is a bit odd ball, one way of considering is to use 3 A-M-C Advanced Motion Controls 100A25 units, the only thing is they do not have a power supply but if you can use the existing DC from the old control (or build one from an existing 3 ph 165v transformer) , these units take up to 250dc and will supply 50 amps ea and 100amps peak, They are probabally much smaller than your exsisting units and if you set them for use in the torque mode you do not really require a tach.You may have a problem getting something that has the same 165v 3 ph input.
Al

[motordude]

Hello Al,
thanks for your reply. The Simoreg is a combined unit (inside a box). Each axis has one N-board (electronic signal board) and one A-board which is the rectifier board. Then there is a common board called the GO to where all boards are connected.

If I replace the Simoreg I would need a new rectifier, which is no problem.

From the manual: "Velocity feedback to the servo unit is supplied by a DC tachometer. The command voltage from the A900 CNC is summed with the tach voltage to create a velocity error signal. The error signal is summed with a current feedback signal to create a difference error. This error is used to control the switching transistors which produce the PWM output to the servo motor"

This doesn`t say me much, but could I really just omit the tach?

regards
John

[Al_The_Man]

John, Yes on modern drives there is the option to do away with the velocity loop, which is what the tach feedback is for. If you used these drives, they have the option, but I would try them in the torque (current) mode, the feedback loop is closed with the resolver back to the control. Usually the biggest precaution in this mode is to not enable them until they are under control, in other words the control is on and working OK and there is no e-stop condition.
They have +- 10 analogue input and enable-in and fault-output. The physical size of one of these is 9.25"x7.21"x3.64".
I assume you have a 165 v 3 ph transformer now so you would just need a three ph rectifier and some big electrolytics.
Al