Hi, I want to closely match the speed of 2 12vdc motors that pull about 4 Amps. I want to put a speed controller on one of them to tune it so that it matches the other. Is this possible by using a large 100W variable resistor? also to match the speed in both directions would i need 2 of them or can you run the raviable resitor in reverse polarity mode?
2007-02-23 08:12:48 · 2 answers · asked by Robbie D 1 in Science & Mathematics ➔ Engineering
In theory using a variable resistor would work and it's not polarity sensitive and not very accurate. How accurate do you want the speed match to be, and would you like to match the speeds automatically?
If so, your best option for accuracy and consistency would be to use an optical sensor on both motors to read RPM and put both outputs into a comparator circuit. The difference coming from the comparator circuit would control a Triac speed controller to adjust the speed of one of the motors. Both of these circuits are available in any hobby circuit manual and can be easily constructed.
2007-02-23 09:08:32 · answer #1 · answered by Gordon B 4 · 3⤊ 0⤋
You need to specify what type of motor you have. There are two basic types: DC - is it a shunt motor or a series wound motor? a resistor can be used for speed control of both of these but the characteristics are different for each. AC - is it single or 3 phase? the only type of ac induction motor that can use a resistor for speed control is a wound rotor type. For standard induction motors you need an electronic device that varies the frequency, but bear in mind that the power output will be less at lower speeds for the same supply voltage.
2016-05-24 03:15:01 · answer #2 · answered by Anonymous · 0⤊ 0⤋