Choosing fuse and pre-charge resistor for RoboClaw 2x7A setup
Posted: Thu Jan 31, 2019 5:46 pm
Hi! I'm working on setting up a single RoboClaw 2x7A to drive two gearmotors, and I'm having a little bit of trouble understanding and sourcing the fuse and pre-charge resistor that I need to get. I have an intermediate level of hobbyist electronics knowledge (mostly low-voltage digital systems like Arduino and custom PCBs), but I'm not as confident when it comes to analog electronics and theory.
Here are the important bits about my set up:
Here is a fuse that I think *might* be appropriate - am I on the right track? It's a 3.15A, 250VAC, fast-acting fuse. Do I instead need a fuse that is rated for a DC voltage? https://www.digikey.com/product-detail/ ... ND/1009002
Also, for my pre-charge resistor I was thinking of using a 1k, 0.5W resistor as described in the user guide, but I wonder if I should use a smaller value since my motors are fairly low lower compared to what the RoboClaw could handle. The RoboClaw 2x7A datasheet says that this value gives a pre-charge time of 15 seconds with 60VDC motors. It'd be nice to not have to wait as long for my setup to charge up before I can start using it, if possible! If so, how do I calculate or choose what the value should be? Or do I really need to purchase a bunch of <1k, 0.5W resistors and experiment?
Please let me know if there is any more info I can provide!
Here are the important bits about my set up:
- A single RoboClaw 2x7A
- Using a 24VDC power supply (not batteries)
- My motors have a stall current of 1.75A
Here is a fuse that I think *might* be appropriate - am I on the right track? It's a 3.15A, 250VAC, fast-acting fuse. Do I instead need a fuse that is rated for a DC voltage? https://www.digikey.com/product-detail/ ... ND/1009002
Also, for my pre-charge resistor I was thinking of using a 1k, 0.5W resistor as described in the user guide, but I wonder if I should use a smaller value since my motors are fairly low lower compared to what the RoboClaw could handle. The RoboClaw 2x7A datasheet says that this value gives a pre-charge time of 15 seconds with 60VDC motors. It'd be nice to not have to wait as long for my setup to charge up before I can start using it, if possible! If so, how do I calculate or choose what the value should be? Or do I really need to purchase a bunch of <1k, 0.5W resistors and experiment?
Please let me know if there is any more info I can provide!