Potter & Brumfield to Bosch Relay

[Hat52MY]

I have an old Potter & Brumfield (P&B) relay that is no longer in production. I would like to replace with more readily available 5 pin Bosch relay. I'm not really familiar with the P&B relays, other than they where high quality. What would be the proper pin conversion from the P&B to Bosch? Appreciate the help...thanks!

P&B => Bosch
1-C =>
2-NC => 87a
3-NO => 87
4 =>
5 =>

 

[Captain Ralph]

1-C => 30
2-NC => 87a
3-NO => 87
4 => 85
5 => 86

 

[Hat52MY]

Thanks Ralph. This is a relay on the Wesmar Bow Thruster. What has me so curious, based on the wiring diagram, the relay appears to be a grounding relay that enable the solenoids. So, if the relay is activated via Thermo Switch, it would open (NO) the ground on the circuit and disable the circuit (remove ground) for bow thruster switch, preventing any solenoid from being activated. Are these assumptions correct?

1-C (30) = ground (to activate solenoid)
2-NC (87a) = ground
3-NO (87) = Not used (no wire connected)
4 (85) = Power (24v DC)
5 (86) = Thermo Switch (ground)

 

[cww]

Those are super common, there’s no need to reinvent the wheel.https://www.ebay.com/itm/353089618639?hash=item5235c802cf:g:2mEAAOSwdnhez5j~

 

[Hat52MY]

Agreed, not looking to reinvent...was just looking to fully understand how this Relay worked and if needed, could determine how to bypass or replace with a Bosch relay more easily procured in the islands. Thirst, or in this case - thrust, for knowledge.... ;-)

 

[Captain Ralph]

Are these assumptions correct?

IMO, Yes.