This method of speed control requires some form of speed sensor, normally mounted on the motor shaft. This block diagram shown below is a typical closed loop control system, which can be designed either to operate analogue or digitally. Hall sensors and opto sensors are commonly used with digital controllers, whilst analogue circuits often use tacho-generators. With PWM control it is possible to achieve good accuracy, flexibility, and reduce power losses. The voltage on motor terminals is the sum of back EMF and the voltage dropped over the coil resistance. The voltage drop on the internal armature resistance is dependent on the motor current and therefore on the load torque.

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Post a Comment. Pages Home Chrono Data Archive. Saturday, October 19, Nitron Technical Observations. This is probably a Part 1 since this is an ongoing project, but I am working occasionally but steadily on a 'Tron overhaul for an HvZ player at a nearby campus.

Along the way I came across 2 odd details about the stock Nitron electrical system. One is that the pusher is cycle-controlled with the switch mounted on top of the battery box that follows the stepped edge of the cam disk but there is no active braking. Except it makes sense in combination with the next bit, which makes AB difficult to implement in the stock configuration.

This strange heatsinked 4-pin package hanging off the side of the PCB is the first thing many people notice about the stock motor setup on the 'Tron pusher. Speculation has included that the device is a voltage regulator or a MOSFET used for solid-state switching of the motor power with the small switches scattered all over the Nitron's guts for various interlock purposes.

At least people are aware you have to remove this PCB to do anything useful. As it turns out, "voltage regulator" is a very close guess. A quick Google nails it down what the mystery component is: a linear motor speed control IC. More or less a fancy linear voltage regulator that allows taking into account the motor IR and Kv in the selection of 2 external resistor values to get a very stable constant-speed, governor-like behavior.

Peak current handling is 1. Sounds awful low. Applications listed in the datasheet include tape decks and CD players. So why was this component used to drive the Nitron pusher motor? That is the biggest mystery of them all. Could there possibly be a need for that tight of speed control of this motor? Surely if the stock setup demanded a lower ROF than the direct-driven motor would produce and no colder-wound motor was available, you could do well enough with a dumb, cheap, string of diodes - or even a generic voltage regulator.

Could it have something to do with dropout voltage? Haven't checked, not worth the time to investigate the numbers of this application. This is why throwing higher voltage batteries at a stock 'tron makes the flywheel rev higher, but doesn't change the terrible ROF. No comments:. Newer Post Older Post Home. Subscribe to: Post Comments Atom.


AN6651 Circuit. Datasheet pdf. Equivalent



AN6651, TO-126-4



AN6651 Datasheet


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