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Author Topic: MAKE THIS SIMPLE MOTOR STALL PROTECTION CIRCUIT.  (Read 2605 times)

rathikrishna

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MAKE THIS SIMPLE MOTOR STALL PROTECTION CIRCUIT.
« on: December 28, 2010, 12:37:33 PM »

Friends, all we know, that, one of the real threat, while playing with RC ships and boats is MOTOR stalling, means jamming of the motor with many reasons.first one is stranding the propeller on anything from a weed to nets, and jamming brush also can cause stalling. the jamming of the armature,makes ample of heat, as it drops a high degree of Amperage, cause potentialy disastrous results.one of the ever simple damage inflicted by this incident is burning of the ESC we used. a heavy money loss will occur instantly. here i am posting a simple proven circuit, for years, to protect our entire unit.

 as we can see here, some simple components are used.here transistor BC77 ,metal case acts as a temperature sensor,as its leakage current differs ,accordance with the temperature it stands.this variation is used for biasing an other transistor,and triggering circuit.BC 108 is used as a buffer amp between the sensor and triggering circuit.AC 128 is used to drive a relay here.we can simply adjust the temperature by adjusting the 470Kilo Ohms potentio meter.we can use any general purpose transistors here, but take care to take only metal case transistors as sensors.

how it helps us..? 

Here the answer...when a stalling occur, a great heat will produced on the ESC, and motor itself.so we now theres always will be a safest maximum temperature levels, as we use our crafts in water.we can simply fix the metal cased transistor, on ESC, or motor by a simple aluminium clamp or by a screw.then we can adjust the value of the biasing voltage by reseting the 470 K ohms resistor.

we can set the preset, just above the maximum temperature after running our craft for several minutes.so when a high heat sensed by the sensor it triggers the other.instantly the relay energised. opening the DC voltage line to the ESC circuit. so we can save our ESC and motor simultaneously.

this circuit can be used on any circuit as a thermal protection circuit, or can be used for switching off a oven, closing a door as sun hets up, or switching a fan on when room temperature increases,or can be switch on A/C.

when this circuit shuts off a system, never try to re open throttle again.it must need a thorough inspection for any jamming of the motor,  or for any short circuit.for a constant vigil, this circuit need a stabilized power supply. for this we can simply use any voltage regulators ranging from 7805 to 7812 ics.its simple.
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wombat

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Re: MAKE THIS SIMPLE MOTOR STALL PROTECTION CIRCUIT.
« Reply #1 on: January 03, 2011, 10:03:39 AM »

Given that the things that are likely to stall the motor will lock the system requiring the boat to be recovered - wouldn't it be cheaper just to use a fuse?

Looking at the cercuit, though, I notice the sensor transistor is connected as C-E with the base open. Normally , you short base to emitter to get a diode and rely on the voltage shift - 2mV/C as I recall.

Wom
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rathikrishna

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Re: MAKE THIS SIMPLE MOTOR STALL PROTECTION CIRCUIT.
« Reply #2 on: January 04, 2011, 01:09:46 PM »

Yes sure..Friend..we can go for many alternate with this circuit...and also can be use a THERMISTOR...and NOW  all of my crafts are are fitted with a second simple propultion to recover my crafts.so when this circuit triggers the second one will start instantly...by relay..so my craft will be driven towards bank...
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malcolmfrary

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Re: MAKE THIS SIMPLE MOTOR STALL PROTECTION CIRCUIT.
« Reply #3 on: February 15, 2011, 07:41:59 PM »

I saw a circuit in an electronics mag many years ago that used a germanium transistor as the sensing element.  It, too was used open base, and used changing temperature as the biasing agent.
Thermistors are good, too.
A circuit like this, if it shuts the boat down, will give a chance of limping back in, a fuse gives a chance of a recovery operation.  If I manage to gather a clod of weed or length of fishing line, if I remember, a bit of tickling in reverse often allows either backing the boat back home, or dislodging enough of whatever has caused the stall to allow a slow return.
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