Home |
Search |
Today's Posts |
|
Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to rec.crafts.metalworking
|
|||
|
|||
Cheapest easy DC motor to survive locked rotor
Ignoramus8558 wrote:
We were playing with my son last night and made a toy railroad gate. It would open and close based on a relay signal from a momentary switch that is activated when a train comes near the railroad intersection. It worked, kind of. My problem is that the DC motor (pulled from a demolished HP X-Y recorder) would overheat from being under power constantly. I would like to find a little 12 VDC motor that could survive a locked rotor condition indefinitely, or some other simple solution. A little solenoid with a dual coil (pulling and holding) also comes to mind. I need something that can be bought for a few bucks at most or made easily, and I am out of ideas. i Put a resistor in series with the motor windings. The unloaded speed won't be affected much, but the stall current will be. You could get fancy and order a polyswitch from Digi-Key -- they are little resistors made of a polymer material with a strong positive temperature coefficient; they work like little resettable circuit breakers. The nice thing in this application is that they're slow to turn off and they hold their value automatically. Their mechanism is entirely thermal so if you tape the thing to the motor case it'll tend to go off sooner when things are toasty. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Re. Rotary phase converters - magic or myths | Metalworking |