Power supply shutting down

[7733star]

I have finally got everything working on my 2dof system. I have been powering it with a dc battery from a car which works fine. I planned on using a power supply with the battery to supply power but the problem I am having is the power supply shuts down with the battery connected. I am using a high end pc power supply that claims to provide max 60A on the 12v rail. I modded the power supply by removing all power wires from the pcb and then soldering in a 10 gauge positive and negative wire to the 12v rail. I connected the positive from the power supply to the positive of the battery and the same with the ground then the positive and negative to my sabertooth 2x60. I does work together for a short time but the power supply soon turns off. I have been doing some reading and it seems that I am getting reverse current to the power supply when the motors change direction. Not sure if I am right about that but it seems to be the case. I tried to power the motors with just the power supply and it turns off with the first movement of the motors but with the battery connected as stated earlier it does work for a short time and then shuts down. Most people are talking about a diode to block the reverse current but I am not sure how wire that to the power supply.

Thanks for any help.

[micma80]

Hi, you can test in follow mode, with a continuity tester or multimeter in ohm you make sure
that positive and negative motor dc poles aren't to mass,
Micma

[7733star]

Thanks micma80 for the information. I have found out that it somehow is the power supply. I tested 2 other power supply and they both worked fine. For some reason the supply I wanted to use shuts down soon after starting. Maybe the power supply is very sensitive to voltage spikes or maybe the supply is just bad I can not find the answer for sure.

Just to make sure I understand what you said you want me to check the ohms across to motor leads to make sure that it is not very high ohms. I will try that and see what happens. I get about 1.4 ohms on each motor. Thanks again.

[micma80]

Hi, maybe psu you want to use is small power, or it is just bad.

For check continuity control I mean between positive pole and motor chassis or between negative plotter and motor chassis. In both cases there must be no continuity, +/mass or - /mass. ok 1.4 ohm between positive and negative pole.
Micma

[7733star]

Ok I checked for continuity for both motors and both motors are ok. I have two PC power supply one is cheap and one is a high end supply Both shut down. I tried a small non pc power supply and it does not shut down but does not have enough power to power the unit. Can I use PC power supply. I have read about people using them but I can not get it to work. Some people have talked about reverse voltage shutting down the PC power supply and to put a diode in the circuit somehow but I do not understand how to do that. Is it worth it to make this work or should I just buy a regular non PC power supply. Thanks again micma80 for your help.

[micma80]

Can you try to power wiper directly without the help bridge (sabertooth) ?
Micma

[7733star]

It is a problem with the ATX power supply I am trying to use. I borrowed a 12v 40amp power supply and it runs everything fine even without the battery connected inline. I am going to try a few things to see if I can make the ATX power supply work but I am just going to buy a proper power supply. With that said I think the problem is I need a load on the 5v rail to make it work maybe.

Thanks micma80 for your help.