Reverse current protection diodes and r/c snubbers

[ControlThis]

Question about protecting plc contacts and other sensitive components from inductive loads. Specifically solenoids that actuate air cylinders (24vdc), electric clutch coils (24vdc and 110vac, and contactor coils(24vdc).
When is it best to use a simple diode, and when is it best to use a resistor/capacitor snubber or suppressor? I've heard diode obviously for the DC stuff and snubber for the ac stuff. I understand a diode won't help me with the ac circuit, but I've seen both diodes and r/c snubbers on dc stuff.
I always use one or the other but not always sure which is best? Any insight would be greatly appreciated.

 

[itsmoked]

You use a diode in DC cases as it is the simplest and most effective technique.

You cannot use a diode in AC for that solution so you use snubbers, (cap/resistor).

Snubbers dissipate power so are less desirable but they work very well.

A suppressor works well and dissipates much less power, only when actually 'suppressing'. Often they have a shorter life as they are mechanical and wear out.

Did this answer your question?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Skogsgurra]

Snubbers are a wide field. Power supplies, motor control and transient suppression in switches are the more important applications. There is a lot of written material.

http://www.multi-contact.com.sg/elesta/images/Technical Information.pdf

http://focus.ti.com/lit/an/slup100/slup100.pdf

http://www.industrologic.com/mechrela.htm

Gunnar Englund

http://www.gke.org

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