Showroom 6DOF Build (Bodine Motors, Sabertooth, FlyPT Mover)

Just took some scope plots of the Bodine 42A motor. Here is the video to go with the plots. @bruce stephen, @cgodwin, this information might be useful to you both.



Scope plots display 20A per division. As you can see that @ no load, on reversing the current draw jumps up to 60A which I believe was clipped by MM. The power supply is rated for 47A. I called Bodine and the only number they give out is "23A rated current"

I think with full load, I will need more juice out of my power supplies. I am thinking about wiring three of HP DPS-600PB power supplies in parallel for two motors and two MMs per motor, which should be enough.

Any thoughts or suggestions would be appreciated.

are you planning on scoping this motor with two motos and two psus?

Absolutely @bruce stephen, thats what I wana do today

Lol, government work today.

Those lever assemblies look familiar My roll lever is about the same CTC as yours using your outside holes, and my pitch lever is much longer. I haven't had any problem driving that, but of course my design is completely different that yours. With your geometry you don't need as much CTC.

I'm still about 2 weeks away from having my sim back together, and then I'll check amp levels. I would guess the PSU's can absorb a pretty big spike. The 47A rating should be continuous, and the big capacitors in the PSU might allow it to handle a 60A spike without a problem. I might have gotten away with it in my case since by JRK's were set to 12A max. I also ran under load, which doesn't necessarily mean more current with a direction change, and could mean less. I haven't had a power supply shut down yet, and I'm using one power supply per motor. But I'm mostly just guessing, and I'll need to run more tests in a couple weeks.

Running 2 power supplies in parallel with 2 motors will give you more safety margin, since it is unlikely both motors will have a maximum spike at the same time.

How are you measuring current? A very low value resistor in series maybe? Or a DC current probe?

With 23 amps rated , you should be considering up to 80-100 amps stall (4x to 5x).

On the other hand, such powerful motors may not even stall at all...

I run two 50amp psus parallel with two motors and 1 mm per motor. It has plenty of power although the mm's run hot during a long rough session (140f). I am currently redoing my controllers to isolate each motor on its own arduino for individual pot scaling and I am going to use two mm's for each motor to reduce the temp and provide additional power for spikes. All three of our designs are very different with greatly varying loads. the 10amp fuse that came with the motors was quickly eliminated.

@BondeX you had also mentioned doing a stall test is this on your list still?

@cgodwin, I am using a Hall Effect DC current probe. How much spike current do you think HP DPS-600PB are capable of ? as you can see from scope plot 2 that even though the PS is rated for 47A, it had no problem supplying more than 47A for about 20ms.

@pipis2015, providing that much power when your home power outlets are 20A each is kinda tough.

@bruce stephen, I will try to conduct stall current measurement when I have the motors mounted, it would be a while before I can conduct such a test as I need to straighten out the electronics.

I agree that you shouldn't run high power with a bolt running through the PCB. The reason for this is the bolt would tend to only make contact in a couple small spots on the pads for the terminal. Those spots will (a) have high resistance, and (b) will overheat under heavy load. On the other hand, soldering wires directly to the PCB will result in excellent conductivity between the two.

That is 20a at 115v but at only 12v you can get very high amperage indeed.

These power supplies draw 8.6A AC Max, So even if I use one circuit for 3 Motors, I need to use two different outlets (circuits) to power the whole thing. If I want to provide 90-100A per motor than I need 12 power supplies and need to use at least 4 different outlets (circuits).

EDIT: Put circuits in ()

Actually, you mean circuits not outlets but I see your point. I have not done the math but I think 12v 200a is possible per 115v circuit. But, I doubt that all of the psus would pull max amps all at the same time.

I put it here @BondeX

Thanks @bruce stephen, so if you ever want to make your ride more or less aggressive, do you play with the PID values or is it done in SimTools?

in simtools, but you can take the kp value down to reduce duty cycle

Also most outlets in the US are 15A, not 20A. A 20A outlet has a horizontal slot coming off the left slot.

The circuit breaker and/or wiring might handle 20A even with a 15A outlet, but it would take a little work to determine if it was really safe to pull 20A even if you spread it between two outlets on the same circuit.

Using 2 (or 4) different OUTLETS doesn't give you any additional capacity than a single outlet unless they are on different circuits. I'm sure @BondeX knows this (he is an EE afterall) but just pointing that out for anyone else who happens to be reading along.

Once my rig is reassembled, I'll measure the total power draw of my setup: 120 VAC and 12 VDC. At one point I had 2 PSU's driving 2 Bodine motors, a gaming computer, 2 laptops, 3 monitors, a big set of speakers, FFB wheel, and an active 3D printer with a heated bed all running on a 15A breaker and didn't have an issue. With short spikes, it all comes down to duty cycle.

Guys which way should the air blow on the heat sinks for MMs? I am using these coolers.

mine point down. same as picture. be sure to trim the tabs off that as @Pit shows here
http://www.xsimulator.net/community/faq/xilence-cooler-for-moto-monster-sparkfun.211/

Already trimmed

From what I am reading, they are saying that it doesn't matter which direction air flow is. I hope they are right

Positive pressure seems to be mostly preferred than negative pressure.