So my question is simple, we know that its good practice to use flyback diodes in solenoid valves and relays, but do pumps and motors also need them as they also have coils?
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1The answer is not simple because it depends on which pumps and motors you talk about and how do you drive them. – Justme Oct 17 '22 at 06:53
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Something like a DC 12 V and DC 6V – Lord Voldemort Oct 17 '22 at 06:56
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3The voltage itself does not define the need for diodes. – Justme Oct 17 '22 at 06:58
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1Perhaps [this question](https://electronics.stackexchange.com/q/322120) will help. – jonathanjo Oct 17 '22 at 07:05
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1Pumps, solenoids and motors don't necessarily need diodes or any form of snubber. The diode isn't there because of the needs of the inductive part. – Andy aka Oct 17 '22 at 10:00
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Flyback diodes are also needed for DC motors and pumps. For AC motors we also need snubbers to limit the voltage transient but usually made of resistor in series with a capacitor.
Paul Ghobril
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The BLDC motor is an AC motor and a driver circuit bundled. The driver circuit contains all the protective gear in order to at all work. If you want to drive the BLDC driver externally, then no, you don't need flybacks. The whole bundle shows no inductance and does not "fly back". – fraxinus Oct 17 '22 at 17:11
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AC circuitry has the benefit of short half-cycles of power, separated by zero crossings. So, an arc on switch contacts is usually short and nondestructive.
Diode clamps are common for suppressing arcing with DC excited coils.
Several other treatments are possible: old house switches were long-span snap action (increases the air gap quickly so the spark extinguishes), newer ones have special long-lasting alloys for the contact points, and occasionally a snubber network (usually a capacitor and resistor) is used, if only to keep radio hash from developing.
The common use of MOV devices also suppresses surges and is compatible with AC power; a diode type device, the V stands for 'varistor', meaning its resistance is high unless applied voltage peaks.
A diode (or back-to-back diode pair) can sometimes be used, but... the other solutions to contact arcing are more common, and work for AC powered circuitry.
Whit3rd
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