Driving dual coil latching microwave relay

[dobsonr741]

I picked up a microwave relay at ham swap to build an antenna switch.

The label reads:
DYNATECH SCM 50667
MOD D1-418D58

The coil config is rather interesting:

- 3 wire driver connection, with common and 1 and 2
- The DC resistance across any pins shows open
- When applying 24V to comm and 1 or 2 it clicks and latches
- Polarity matters: Com is +, terminal 1 or 2 needs to be - to switch

What is the standard driver circuit for this kind of relay, current and timing wise?
 

[joeqsmith]

Maybe just a SPDT momentary contact toggle:
https://www.digikey.com/en/products/detail/te-connectivity-alcoswitch-switches/MTA106G/724912

[Andy Chee]

How about an SCR dumping a fully charged capacitor into the coil (say 2200uF), should give enough of a pulse to flip the relay without burning out the coil from continuous current.

[EggertEnjoyer123]

Connect +24V to the +COM, and use a BJT to connect pin 1 or pin 2 to ground. A microcontroller or something could be used to send the signal to switch.

As long as you have the flyback diode a crappy transistor like the 2N2222 should work. Current is usually < 200mA.

[Randy222]

Connect +24V to the +COM, and use a BJT to connect pin 1 or pin 2 to ground. A microcontroller or something could be used to send the signal to switch.

As long as you have the flyback diode a crappy transistor like the 2N2222 should work. Current is usually < 200mA.

+1

Odd that it only works with +V on the comm terminal. Perhaps they put inline diodes to each half of the coil?

Instead of BJT an nFET (2x) could be better. comm +V and then 1 (2) to drain of nFET with fet source to gnd. Many FETs are avalanche rated, but you can still drop a diode(s) from 1 to comm and 2 to comm, but in blocking direction.