[Jukebox-list] Electronic theorists: What component values for time delay relay?

[Jay Hennigan]

Paul Taylor wrote:
> This is the continuing saga of my attempts to get an AMI  'K' pulse 
> converter operational. I'm having to adapt a relay to take the place of 
> what AMI call the 'Time Delay Relay No. 1' which is faulty (coil is open 
> circuit on the inner end). I have a substitute coil which, whilst the 
> same physically, is lower resistance than the original and won't 'delay' 
> using the 220 ohm resistor shunt set-up of the original.
> 
> Essentially what I need to know is this: Can any electronic theorists 
> suggest / calculate where to start with a combination of resistor and / 
> or capacitor to give a time delay action of 40-60 milliseconds on a 
> 30volt dc / 400 ohm relay coil ?

What are you trying to accomplish?

1. Relay pulls in immediately, contacts stay closed 40-60 ms after 
voltage is removed.

2. Apply the voltage and have the relay pull in 40-60 ms later.

3. Both 1 and 2.

For 1, a 125 microfarad capacitor rated at 50VDC in parallel with the 
coil should get you in the ballpark.  Exact value depends on the relay 
sensitivity.  125 microfarads is one time constant for the values given, 
which drops voltage by 63%.

T=RC, so .05 seconds = 400 ohms * .000125 farads.

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