Solar panel
Just got a 100w panel and want to run a 12v 80w radiator fan, NO BATTERY. The panel is cranking out 23v do I need to put a controller in the middle. All controllers I look at have a battery hookup b...
Forum Discussion
2112 wrote:
"inductance" is an inductor thing. DC motors and solenoids have "inductance" which will create transient EMF with a fluctuating source voltage or current and back-EMF when powered off. Hence the use of a flywheel diode.
DC circuits are not "steady state" 100% of the time. They have to be powered on and off. A low pass LR filter is a common in-rush suppressor on DC capacitive circuits and circuits designed to be hot swapped. It wouldn't work without "inductance".
Regardless, my suggestion of a series diode was to protect from any unknown reaction of powering a large motor
But thanks for the lecture
Brush DC motors even large ones will not have enough "back EMF" to cause issues due to the constant switching actions.
It is no worse than turning a switch on/off/on/off on a DC motor.
LR circuits are typically used in power supplys to filter out any remaining 60hz that may be present from a brute force unregulated powersupply. Has nothing to do with supposed back EMF but all about providing a clean DC powersupply voltage.
Good quality brush DC motors will however have a small value capacitor placed across the input terminals. That capacitor is present to reduce the RFI noise generated by the brushes and switching action of the commutator. Has nothing to due with back EMF but for RFI reduction which can affect radio and TV reception close to the motor.
There are tons of DC motor devices setup and running in this same panel/motor configuration all without any LR, filtering/charge controller or battery. This is often done with pond aeration and ventilation systems which doesn't need to run 24/7.
OP will not destroy the panel running a DC motor directly from it, quit scaring people into spending more on stuff than they need to.
