I have a relay and am confused by its operation.
It is a Potter & Brumfield Relay, model
My confusion stems from the "Must operate voltage" & "Must release voltage" parameters on the data sheet.
The relay in question has a nominal coil voltage of 24VDC.
The datasheet states this:
Operate Data @ 25°C Must Operate Voltage: 75% of nominal voltage or less. Must Release Voltage: 5% of nominal voltage or more.
Based on my interpretation of that block, at 25C, bearing in mind that my relay coil's nominal voltage is 24VDC:
(This does not make sense to me)
- the coil will operate at 18DVC or less
- the coil will release at 1.2VDC or more
I have been doing some testing with my DC bench power supply, my environment is around 26C.
I am finding that the coil will switch/operate at just below 16VDC, emitting a "small" click noise. (This seems to partially correlate with the "Must Operate Voltage" parameter, 75% of nominal or less 24VDC)
When I turn it up to just above 19VDC, there is a louder click - but nothing appears to change WRT to the coil state, nor resistance of the pole->NO pins (the pole->NC pins as well).
When I have triggered the relay, I have found that the coil will release when I decrease the voltage down to 9VDC; and it will stay released until I bring the input voltage back to above 16VDC.
To me, this does not seem to directly correlate to the "Must Release Voltage" parameter (5% of nominal or more)
My questions/confusion can be summed up in a few points:
- What is the significance of the "or [less|more]" in the Operate Data parameters?
- For the release voltage, 5% of 24VDC is 1.2VDC, my relay will release consistently at 9VDC. How many grains of salt am I supposed to take with the "5% of nominal voltage or more"?
- Based on number 2, "5% or more" would mean, to me, that the coil could release anywhere below 75% (Must operate voltage) - is this a correct interpretation?
- For the operate voltage, it says 75% of 24VDC - that is 18VDC, if I am to take the "75% of nominal or less" at face value - the "more|less" seems to be inverted to me. Should I expect it to switch anywhere between 75% or higher? (IE, 18VDC-24VDC) Or should I interpret that as switching anywhere between 5% and 75%+?
Last piece... This may be me misinterpreting the data sheet, but I would like to validate my thinking and verify if I am reading this sheet correctly or not.
I am relatively new to the electronics world, and am picking up knowledge as I go. I've just picked up "The Art of Electronics" by Horowitz & Hill, to try to understand more about this all, but please excuse me if I've misused any terms here.