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Electrical Issues: Hatch Lift - Battletech Pod - Tail Gate Lift Motor
DaOld Man:
Yeah I kinda figured that.
The power supply needs to be beefy, but it doesnt have to be regulated for a motor. A 10 amp transformer with a 20 amp bridge rectifier and maybe one beefy capacitor for a filter should be just fine.
The regulated power supplies are probably not good for motors, since they do have a short circuit protection and may see the motors start up current as a short.
Its not like the motor is going to be running constantly, so I wouldnt go overboard, since a bigger transformer means more floor space needed. (A 10 amp battery charger may be all you need.)
lilshawn:
A Relay will usually end up with stuck contacts if the amperage is too high.
I suspect the power supply output regulator has had enough and is shutting off on you (overload protection)
i wouldn't use that power supply for a computer anymore.
danny_galaga:
To be REALLY sure what the motor does, you should get a car battery like Lilshawn says, and hook up an ammeter (or an induction loop thingo on a digital voltmeter) so you can see what the true current draw is- loaded and unloaded. Just remember that a DC motor draws STACKS of power at start up (because it has an effectively very low resistance) and at speed draws a lot less. For instance your typical car starter might draw 50 amps or so just free spinning, and say 200 amps cranking the engine but if you lock that bad boy up it will be over 500 amps! More than likely a very short duration spike won't effect things but you should get a handle on what's really going on. I myself would be very surprised if it only draws 10 AMPS, but am happy to be wrong. hook it up to a car battery so you have effectively unlimited amps for the motor and measure the current.
You also have to make sure you have enough amps for the motor because you risk burning it out if the voltage drop is too great, which will happen if you overload your power supply. Again this happens with starters. At 12V, it's fine, motor can spin fast. But if your battery is a bit dead and the voltage drops to say 9V, even though you would think that would mean less current draw (V=I x R), it will actually be more because now the motor is spinning much more slowly, and for a DC motor, speed is proportional to resistance. This is when car starters burn out. I'm only using starters as examples because I used to be an auto-electrician and that is where most of the repairs were done. Smaller motors didn't have as many problems, therefore I can't reliably quote figures for them, but the principles are the same...
kahlid74:
--- Quote from: danny_galaga on February 22, 2013, 04:45:48 am ---
To be REALLY sure what the motor does, you should get a car battery like Lilshawn says, and hook up an ammeter (or an induction loop thingo on a digital voltmeter) so you can see what the true current draw is- loaded and unloaded. Just remember that a DC motor draws STACKS of power at start up (because it has an effectively very low resistance) and at speed draws a lot less. For instance your typical car starter might draw 50 amps or so just free spinning, and say 200 amps cranking the engine but if you lock that bad boy up it will be over 500 amps! More than likely a very short duration spike won't effect things but you should get a handle on what's really going on. I myself would be very surprised if it only draws 10 AMPS, but am happy to be wrong. hook it up to a car battery so you have effectively unlimited amps for the motor and measure the current.
You also have to make sure you have enough amps for the motor because you risk burning it out if the voltage drop is too great, which will happen if you overload your power supply. Again this happens with starters. At 12V, it's fine, motor can spin fast. But if your battery is a bit dead and the voltage drops to say 9V, even though you would think that would mean less current draw (V=I x R), it will actually be more because now the motor is spinning much more slowly, and for a DC motor, speed is proportional to resistance. This is when car starters burn out. I'm only using starters as examples because I used to be an auto-electrician and that is where most of the repairs were done. Smaller motors didn't have as many problems, therefore I can't reliably quote figures for them, but the principles are the same...
--- End quote ---
Thanks for the great recommendations! I'll definitely give this a go.
kahlid74:
Sooo, it's been a while since I updated this. Too much stuff going on but i finally got back to this. While picking up grass seed at Menards I grabbed a car battery charger. Hooked it up to my Relay/UP-DOWN button/On-Off Button and boom-shakalaka, it worked like a champ:
So I then had to decide whether I wanted an Arduino to power it or a Raspberry Pi. I had one of these "PiFace" electrical boards that has 8 inputs and 8 outputs and two 10AMP relays built into it. So I decided what the heck, lets build it on Pi. So I'm going to use a 3.5" LCD screen as the main login screen and a USB numpad as the keycode enter system.