Running PD Board from an outlet

[innoying]

By "not friendly" you mean they are only going to work for a specific setup? If so, what is it looking for? I've moved on to the idea of using a laptop 12 volt power supply instead as it would probably be closer to the correct voltage and provide enough current. If I knew what they are looking for I can try a different power supply that is more appropriate easily.

[aire]

Could you use a desktop power supply like this to power the whole robot with motors and all? At 12V/135A, it provides more current than the main breaker can handle anyway, right?

[innoying]

Where did your 135A stat come from?

[aire]

12V@135A is listed on the spec page on newegg for the linked power supply.

[engunneer]

A pc power supply like the one from newegg could run the robot.


to power it on, connect the thin green wire to ground on the motherboard connector.

[EricVanWyk]

If you just want to program things and not make anything move, any clean 12V >30W power supply will do. The original part linked is likely to put out incredibly dirty power, I would not try it. The power supply module linked will likely work nicely.

Be sure not to use the battery charger as a make shift power adapter - they can interact poorly.

[Cuog]

If you're making and buying things, why not just get an extra charger, it will likely have more uses to you and your team.

[aire]

Eric,

What power supply wattage would be needed to run motors off of?

[engunneer]

Decide how much power the motor takes. Worst case for a CIM on a 40A fuse is going to be 12V*40A = 480W coming from the power supply. Add up all the motors you want to use to get a worst-case idea.

with a 500W power supply, you can test 1-2 motors at a time under full load. If your wheels are not on the ground, they are not at full load, so maybe you can run 4 motors or so.

[EricVanWyk]

Originally Posted by aire

Eric,

What power supply wattage would be needed to run motors off of?

For a full robot on the ground? Somewhere in the range of 2-6kW.

For testing subsystems while up on blocks? 1kW might do it.

Originally Posted by engunneer

Decide how much power the motor takes. Worst case for a CIM on a 40A fuse is going to be 12V*40A = 480W coming from the power supply. Add up all the motors you want to use to get a worst-case idea.

with a 500W power supply, you can test 1-2 motors at a time under full load. If your wheels are not on the ground, they are not at full load, so maybe you can run 4 motors or so.

Actually, a CIM can easily draw 100-130 Amps at stall depending on wiring. When a breaker has a 40 Amp rating, it means that it can sustain 40 Amps indefinitely.



EDIT to add:
Regenerative breaking can play havoc with some power supplies. Where a battery would simply accept the regenerated charge, some power supplies will go high-impedence to protect themself. The voltage can spike and destroy the supply or the robot electronics.

[FrankJ]

For just powering the electronics, a small 12 volt power supply will work. I imagine you could dig one out of an old computer.

To survive a regional you are going to need lots of batteries and an extra charger. So buying that now would be a good idea. If you are not running motors or running them lightly loaded, the robot battery lasts a long time.

[MAldridge]

I second the computer power supply. Ask your school's tech department if you can get a power supply out of a dead computer. Those can easily put out a huge amount of clean current (I currently use one to drive the stereo in my school's NOC).

A word of warning though, those can put out dangerous amounts of current, make sure you know what you're doing when working with it.

[andreboos]

I've used a car battery charger to power a minimal control system (digital sidecar, cRIO, camera, single motor) through a power distribution board. I'm guessing this power isn't much cleaner than that from the car adapter. Does the dirty power permanently damage parts or is it simply unreliable?

I have also used a PC power supply to power the newer cRIO directly (accepts as few as 9 volts) but have not attempted to power anything through the PDB.