Current set resistor

[native34]

I have 6A per phase motors and on the gecko G203V it says with that amperage use a current set resistor that is 282Kohms but the only thing close to this is 270Kohm or 300Kohm can i go with the 300Kohm or do i need to use the 270Kohm

[tauntdesigns]

Originally Posted by native34 I have 6A per phase motors and on the gecko G203V it says with that amperage use a current set resistor that is 282Kohms but the only thing close to this is 270Kohm or 300Kohm can i go with the 300Kohm or do i need to use the 270Kohm

On the outside of my G203v, there is a chart printed on it. 6a = 270k

I think I would error on the low side. The stepper may not like the extra amperage....

[kawazuki]

How do I obtain 3500 ohm resistance? My motors are 4A but being run on a
G540 so 3.5A max........3.5 x 1000 = 3500 ohm or 3.5k ohm? What combination of common values will give me the above?

[tauntdesigns]

I was going to give a link to Mouser electronics, but then noticed you were in the UK.

I've been hunting for a supplier that has 3.2k in single qty. Mouser and Digikey has a min order of 1000 pcs. Don't need 1000 resistors. Although I was able to get 2.8k in single qtys. from Digikey.

Mouser does offer 3.5k in singles (Digikey 1000 min)

Sorry I couldn't help, Maybe somebody will be able to,
Jack

[kawazuki]

I believe I can get 3.48k ohm from RS here in the UK with 0.125w rating. I guess the resistance is ok - what about the rating? Will this be sufficient for a current set device? RS will happily sell in 10's and then only cost pennies / cents - as you say don't really need 999 spares !

[tauntdesigns]

G540 Manual - (The resistor can be from 1/10 W to 1/2 W in size and 1% to 5% tolerance.)
1/10W(.100) - 1/2(.500)
.125 falls inside the range given in the manual

[Wolfesmetalfab]

will these resistors work for a 6.1amp motor setting on G203s? Might be a good source for others as well, as 5 pieces is just right, and they are cheap! The metal film is fine to use, right, i mean it doesn't matter what type of resistor does it? Also it has 1% instead of 5% tolorence, but thats fine, or even better, right?

280k for 6a motor

316k for 6.1a motor (318.5k is equation answer)

[CarveOne]

Originally Posted by Wolfesmetalfab will these resistors work for a 6.1amp motor setting on G203s? Might be a good source for others as well, as 5 pieces is just right, and they are cheap! The metal film is fine to use, right, i mean it doesn't matter what type of resistor does it? Also it has 1% instead of 5% tolorence, but thats fine, or even better, right? 280k for 6a motor 316k for 6.1a motor (318.5k is equation answer)

1% is better, but not required. There are more 'standard value' choices available in 1% tolerance than in 5%. 316k should work fine. Note that 7amp shows OPEN (no resistor). Mariss has said in other threads that if the resistor value is too high you can have the G203V go into thermal shutdown from heat rise. If you never see that happen with a 316K resistor then you are operating at an acceptable resistance value. Extra heatsinking and a cooling fan on your G203s should help ensure no shutdowns occur.

Metal film resistors with leads may have too much inductance for high frequency circuits but should not be a problem for these drives. Depends on the circuit design's sensitivity to small inductance values.

An online parallel resistance calculator is at http://www.1728.com/resistrs.htm and can calculate for up to 10 resistors in parallel. If you need something like 3500 ohms (3.5K) double that value (7100) to start with. Then pick the next higher and the next lower standard resistance values and see what that gives you. You can then raise the higher standard value to the next higher value again to raise the parallel resistance, or lower the smaller value resistor if you need to achieve a slightly lower parallel resistance.

CarveOne

[hpghost]

hi,

on the G201, if you link a motor of 6A, shall the set resistor set for 6A or 67% of 6A?

[LaserImage]

Originally Posted by kawazuki I believe I can get 3.48k ohm from RS here in the UK with 0.125w rating. I guess the resistance is ok - what about the rating? Will this be sufficient for a current set device? RS will happily sell in 10's and then only cost pennies / cents - as you say don't really need 999 spares !

That's what I used and it works fine.

Gary

[Wolfesmetalfab]

on the G201, if you link a motor of 6A, shall the set resistor set for 6A or 67% of 6A?

It should be set at 6 amps, or you will limit the motors top performance. That is a good question though, sounds like something I would come up with, after overthinking a situation! LOL

The 67% rule for power supply, is because you are never going to be pulling the full load on every motor, so you dont need to have enough power to do so, but the individual motors may pull 6 amps or close every once and awhile, thats why you need to have the current set resistor set at 6 amps in your situation.

Does that make sense?

[hpghost]

I was on that understanding an your confirmation is good.

will go ahead with this setting