> i think that we can follow/try out most of your suggestions w/o any (or very little) electrical/electronic training
Yeah, that was the idea !
> i don't know if the Multimeter we have will measure amps, i think it does, but am not sure how to do this
OK, if you got 2 multimeters, wire them like this (on my doodle : wall wart, voltmeter, ammeter, motor) so you can read volts and amps. Change the motor polarity manually to make it go in the right direction.
Online Sketch: Untitled Sketch by Anonymous Author
If you only have one meter, you'll have to make 2 measurements.
Remember, current goes through ammeter so it can measure it. The ammeter is like a piece of wire (very small resistance actually) so don't plug across on your wall wart to check how many amps it can supply
Use the 10A ammeter setting, that should do the job, no need for great precision.
You need to know :
- the max current the motor needs (look at the amps) to size the power supply, driver, and protection
- the current with motor stalled (only for a few seconds)
- if your powersupply can supply it (watch if the volts stay constant)
Counter-intuitively, a wimpy power supply will burn your motor : not enough power, the motor stalls, then it burns. A powerful enough supply will allow the motor to not stall, unless of course it hits the end of travel limits, or there is something blocking the rotation, in which case the polyswitch should protect it.
The screw thing is good, should give more torque.
> The two power supplies question!!!???
Well, that's simple, it saves a couple transistors and resistors (about $1), plus some headache, to the guy who makes the kit.
> Where would the Polyswitch go?
In series with the motor, like a fuse. You could put it in the power supply (but you got 2 supplies), however if it trips, the tracker will lose part of its power supply, I wonder what it would do...
Once you measure your motor, we'll see about the rest...