Voltage regulator heat
06-30-2006, 11:48 PM
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Voltage regulator heat
How much heat is normal for a 6.0 volt regulator? Should it be warm to touch or really hot?
I am using 7.4 volt LiIons with 6.0 volt regulators. My servos are analog servos.
I am using 7.4 volt LiIons with 6.0 volt regulators. My servos are analog servos.
07-02-2006, 10:22 AM
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RE: Voltage regulator heat
The same principle applies to all typical linear regulators used in RC, with the exception of the switch-mode convertors. The amount of heat generated by the regulator is a function of the voltage across the regulator (7.4V-6V = 1.4V) and the current through the regulator drawn by the servo's (variable, and affected by size and load of servo), and related as P = VxI (power - specifically power loss in this case). It's the power dissipation that causes the heating.
So if you use a 3 cell battery pack, the heat generated will be more than if you used a 2 cell pack - assuming the same servo's and load.
There is a way to calculate the minimum rating of the regulator for a given set of servo's, but it can often be difficult to get the specs you need to do the calc's in the first place. Manufacturer's typically tell you size and quantity of servo's that can be used with a given regulator or BEC.
Now in terms of heat, generally speaking if it's too hot to touch and hold, then it's too much. But our planes provide cooling airflow, so a regulator will normally run much cooler in the air, than on the ground(with the motor off).
I found that the best and quickest test, is to wiggle all the control surfaces rapidly and together (with motor off - thus no airflow) for 15 - 20 sec, and observe if the regulator shut's down or if power glitches to the servo's (indicating regulator current/heat overload).
If all OK, the regulator is adequate - go fly.
So if you use a 3 cell battery pack, the heat generated will be more than if you used a 2 cell pack - assuming the same servo's and load.
There is a way to calculate the minimum rating of the regulator for a given set of servo's, but it can often be difficult to get the specs you need to do the calc's in the first place. Manufacturer's typically tell you size and quantity of servo's that can be used with a given regulator or BEC.
Now in terms of heat, generally speaking if it's too hot to touch and hold, then it's too much. But our planes provide cooling airflow, so a regulator will normally run much cooler in the air, than on the ground(with the motor off).
I found that the best and quickest test, is to wiggle all the control surfaces rapidly and together (with motor off - thus no airflow) for 15 - 20 sec, and observe if the regulator shut's down or if power glitches to the servo's (indicating regulator current/heat overload).
If all OK, the regulator is adequate - go fly.
