Quick G540 question

[SatanKlawz]

If you have the latest revision of the G540 do you still have to solder the resistors in place on the connectors?

[aarongough]

Yes, you have to solder a current set resistor between pins 5 & 9 (if I remember correctly) in the DB9 connector that you use.

I assume I have the most recent G540 as I only bought it about a week ago.

It's a great drive!

[DonFrambach]

Although it is clearly stated in the Gecko documentation, just want to emphasize that it is important to place the resister on the side of the cable next to the G540 and not the side near the motor. Here's a link that makes clear why that is important: http://www.cnczone.com/forums/diy-cn...40_info_-.html

[aarongough]

Originally Posted by DonFrambach Although it is clearly stated in the Gecko documentation, just want to emphasize that it is important to place the resister on the side of the cable next to the G540 and not the side near the motor. Here's a link that makes clear why that is important: http://www.cnczone.com/forums/diy-cn...40_info_-.html

Interesting... I have the CNC Router Parts 3 axis kit and I have noticed that the motors are getting far too hot, perhaps this is part of the reason.

I have contacted them to ask for more details, I'll post back when I hear more. For the moment I am going to attach some 80mm fans to each of the motors. It's *really* amazing how much difference a little airflow makes to the temperature...

[ssutton]

I have my G540 set to 2.8 amps and I am using automation direct 276 oz on motors. After 1 hour of continuous operation my motors measure 140 degrees F. Stepper motors are supposed to operate hot if they are sized correctly. How hot is too hot I do not know, but I have been told that if you can hold the motor after it has been operating for a while then it is probably not sized correctly, it should be too hot to handle.

[aarongough]

Originally Posted by ssutton I have my G540 set to 2.8 amps and I am using automation direct 276 oz on motors. After 1 hour of continuous operation my motors measure 140 degrees F. Stepper motors are supposed to operate hot if they are sized correctly. How hot is too hot I do not know, but I have been told that if you can hold the motor after it has been operating for a while then it is probably not sized correctly, it should be too hot to handle.

I've heard the opposite a number of times, that if the motor is too hot to handle for at least a few seconds, then you're running it too hard. I'm not sure what the rated temperature of the motors is though to be honest. I would expect that hot is fine, but being able to cook an egg is probably too much...

Just talked to Ahren at CNC Router Parts and he said that some of the G540s are sensitive to the placement of the current set resistors and some are not. My g540 appears to be a sensitive one as he seems to think I shouldn't see motors that are as hot as they are...

[aarongough]

Not to further hijack this thread, but:

After a little research the motors from CNC Router Parts are built with 'class B' insulation. Class B insulation is rated for 80oC (170oF). I'm getting an infrared thermometer tonight and I will be checking my motors when I get home.

80oC max for stepper motors seems like a good rule of thumb. Cooler is better for motor life though (fans help a lot! You might be surprised!)

[DonFrambach]

Many of the parts of my router including the motors and G540 came from CNCRouterParts.com. I too had very hot motors. I rewired the motors as per Gecko instructions and they now run much cooler. I would suggest you do that rather than use fans. The motors are getting hot because something isn't right.

A while ago Ahren mentioned in a post here that he has manufactured a short cable with the resisters to insert between the G540 and the extension cable. Rather than use Ahren's cable, I chose to install the motor covers from DY Engineering that required that I make the cables. That is a cleaner installation that you may want to consider.

I posted some photos of the cable covers in post #89 of my build log: http://www.cnczone.com/forums/diy-cn..._router-8.html

[aarongough]

Originally Posted by DonFrambach Many of the parts of my router including the motors and G540 came from CNCRouterParts.com. I too had very hot motors. I rewired the motors as per Gecko instructions and they now run much cooler. I would suggest you do that rather than use fans. The motors are getting hot because something isn't right. A while ago Ahren mentioned in a post here that he has manufactured a short cable with the resisters to insert between the G540 and the extension cable. Rather than use Ahren's cable, I chose to install the motor covers from DY Engineering that required that I make the cables. That is a cleaner installation that you may want to consider. I posted some photos of the cable covers in post #89 of my build log: http://www.cnczone.com/forums/diy-cn..._router-8.html

So it turns out that although the motors are getting hot, technically speaking they're not getting 'too hot'...

The insulation in those motors is rated for 80oC. After running them for 3 hours, the temperature of the motors rose to a maximum of *exactly* 80oC measured with an infrared thermometer.

CNC Router Parts are sending me a new set of adaptor cable which should lessen the heating somewhat, I will also be installing fans to actively cool the motors which should increase their service life.

[Mariss Freimanis]

Motor Temperature:

Kollmorgen step motor literature specifications are typical and rate the maximum motor temperature as 100C. Other manufacturers use an 85C temperature rise as a maximum rating. Standard ambient temperature is 25C, so an 85C spec would take the motor case temperature to 105C.

G540 Current Set Resistor:

The current set resistor must be located on the DB-9 connector and not at the motor end of the cable. The motor will get hotter and run rougher when the resistor is placed at the motor end of the cable. The next revision of the G540 will not have this restriction.

DB-9 Connector:

Please use the Geckodrive supplied DB-9 mating connectors or make sure an alternative connector is rated at 5 Amps per pin. Many inexpensive DB-9 connectors are rated at 1 Amp per pin and they will overheat at 3.5 Amps.

Mariss

[SatanKlawz]

I already have one G540 running. I bought it a few years ago and its been great. I just bought another for a new machine and I thought I had read somewhere that soldering in the resistors was not necessary anymore. I guess not. Its no problem to me as I have already done it once.