I've had a problem with the subject relay that involved modifying a spring to replace the original, which had been distorted by a previous owner, rendering the relay inoperative. The new spring seems to be working well, giving a good positive latching action in either direction.
My question concerns testing the relay to ensure that it still trips at the correct over-current. According to the manual for the CT80 version this occurs when approximately 200mA flows in the relay coil. The coil measures approx 22 ohms DC resistance.
I lashed up a simple test rig using a 12V motorcycle battery wired in series with a variable resistor and a DMM; by gradually lowering the resistance the relay trips at about 220mA, which would seem to be a good result.
However, in circuit this relay monitors the current flowing in the transformer centre-tap connection of a pretty standard FW double diode valve rectifier, so as far as I can see, it will be monitoring an AC waveform in real life, rather than DC.
Will this have any significant effect? In other words, is the DC test valid?