Servo Drive Sizing

[GEMorris]

I have some SEM brushed servos on my SCMI Routron which I just bought. They are rated at 4.5nm, drawing 10.2 amps and 57 amps at peak.

What would be a good drive option for these? I want to have a retrofit prepared incase anything happens to the onboard controller, which is ancient.

I can't find peak amp ratings for geckos, I'm assuming I'm going to have to go with something industrial, but perhaps not.

here is the tech sheet, mine are the 48's http://www.sem.co.uk/files/brochure/MT30U4.pdf

[Al_The_Man]

You don't need to supply the peak current, this is the maximum the motor will take before demagnetization. Most drives will allow a set point to go into current limit at the maximum stall current, which is 10.2 amps, I am assuming you are looking at a parallel port/software motion system? If so you are limited to step & direction drives.
You also do not need to use the tach feedback on modern drives.
Al.

[GEMorris]

Al, thanks for the response and info. In that case, I have a second question, which is that my Parker TQ10 drives have a peak amp rating of 10amps, these servos have a peak amp rating of 10.2, is this something I can get away with?

[Al_The_Man]

They mention that that take over 13Nm peak so I would think they would work, you will need the SD version if you want to go step & dir. They are DC brushless amps, however they can be used/set up to drive Brushed motors.
If these are your existing drives, they may be ±10vdc analogue control, in that case you will need a step/dir convertor to use parallel port system.
The parker site also has sizing software you can download.
Al.

[GEMorris]

Yeah, I was planning on using the Motentc 4 axis board with EMC2 as it can output analog. I have two drives with the heatsinks and two without, to run them over a certain amperage you are supposed to have the sinks. Still not sure what motor I'm going to run on the Z (as I have to convert my machine to a Z, SCMI made a 2 axis and 3 axis version, I have the 2).

From what I can tell from looking at this machine's hardware, converting to TQ10's and EMC2 is going to vastly simplify the electronics at least.

[Al_The_Man]

Its always a wise idea to keep drives as cool as possible, if you can fit heatsinks or attached them to a chunk of aluminum, I would.
Al.

[mcpltd]

The Motors you mention have a nominal current os 10.2A.
THe peak current is 57A.
With that driver i am guessing that the nominal current is 5A you will get 2.2Nm only.
If you need a higher current driver we have some surplus axor analogue drivers, that are used in the NEE motion controllers.

Originally Posted by GEMorris Al, thanks for the response and info. In that case, I have a second question, which is that my Parker TQ10 drives have a peak amp rating of 10amps, these servos have a peak amp rating of 10.2, is this something I can get away with?

[unterhaus]

What's the nominal current output for the TQ10? I'd be a little concerned that the peak current of my drive was the continuous max current capacity of my motor. I wouldn't worry about a little mismatch between drive and motor, but that might be excessive. The best case is that the drive can supply too much and you set the limit lower.

Seems like some of the AMC drives would handle those motors. Problem then is getting a power supply. Most of the AMC brushless drives can also handle brushed. The brushed drives seem to go for a lot more on ebay.

[GEMorris]

what about geckos. Is the 20amps the gecko's peak stall or peak continuous amperage?

[mcpltd]

Its 5A and 10A peak

Continuous Current 5 Amps with TQ10-EHS or mounted to heatsink at or below 45°C
Peak Current 10 Amps with approx. 2 sec. maximum duration at 45°C

From the deatasheet.

[mcpltd]

Originally Posted by GEMorris what about geckos. Is the 20amps the gecko's peak stall or peak continuous amperage?

I am not sure, but i think it is 10A continuous and 20A peak.

[GEMorris]

so that would work in this case right? I'm using brushed motors with a contiuous amp peak of 10.2 The 57 amp stall peak doesn't need to be covered does it? What happens when the motor wants more than 20 amps and the gecko can't provide it?