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taperturner · Jul 8, 2007, 01:19 PM

During my National Service in the R.A.F. about fifty years ago, I learned about a type of solenoid or relay which provided a delayed reaction when the power supply was cut. I now think I could use such a device in a motor reversing/braking circuit that I am designing. Unfortunately, I can no longer find my notes on the subject and my memmory is no longer up to it! Can you please tell me what I am talking about? - I seem to recall that a resistance was involved.

acetc · Jul 8, 2007, 02:03 PM

You may be able to use a time delay relay, some delay on coming on and some delay on going off. Most air conditioning supply house's carry these relays, Mike

Gary Peach · Jun 10, 2009, 10:17 PM

You are quite correct; the RAF did use slugged relays.

The relays had a large iron mass at the top of the coil.
Once power to the relay was cut or if power was applied the hysteresis of the iron mass made the magnetic field rise slowly to the point where sufficient flux was available to close the relay or the flux to fall sufficient to release the relay.

Depending upon the logic of the circuit one of the normally open contacts on the relay could be used to hold the relay closed.

Encountered at
RAF Yatesbury, (RADAR MECHANIC)
RAF Henlow
RAF Fairlight
RAF Locking (RADAR FITTER (R))
RAF Benson
RAF Butzweilerhof

401 J/T PEACH, RETIRED, Sir.

Now, does anyone have any of these beasts?

I want one to stop a Grunfos Shower pump from hunting when other taps in the house are turned on or off; (it keeps the grandson awake in the middle of the night, when he should be getting his beauty sleep).:rolleyes:

Has anyone tried solving this problem?