Master solenoid diode?

[Jch]

My starter solenoid came with a diode, but the master solenoid didn't. Aircraft spruce sells a diode for the starter solenoid but not for a master. The question is, does my SS7 with 912uls need a diode across the master relay and if so is it the same or different from the starter solenoid? Can I order and install the ACS diode? Thanks for the help.

[Danzer1]

This is the best explanation of diode use in relays/solenoids/contactors: http://verticalpower.com/_documents/...tor_wiring.pdf

In their description the battery contactor is the master contactor. Also pay close attention to the direction of the diode - the end of the diode the stripe is on, must be on the appropriate end it connects to (as they show).

Greg

[Jch]

VERY! Helpful! Thank you for directing me to that link. I will order the same diode for the master. If I am seeing it correctly, the starter relay diode goes from the switch to the mounting plate ground and the master relay goes from the switch to the battery side terminal. Why wouldn't the master go to the mounting plate ground? Jch.

[Jch]

Danzer, after studying the information you sent me I can answer my own question. The direction of current from the switches is different. Then, the diodes will attach to the two relays switches differently as well. I took a picture of a firewall at Oshlosh and I though the diodes attached to the relay switches in the same direction but they don't. Thanks again for leading me to the answers. Jch

[Danzer1]

Glad to help. Can't stress enough though - make sure the stripe on the diode is on the correct side.

Greg