I am thinking that the symbols that look like capacitors (in my day) are switch contacts. Why does one have a line through - does it mean 'normally closed' perhaps.
I need to fit this as a replacement in a fridge freezer and the terminals are different. When I get it I can put a meter on it - but would like to understand it in advance.
yes your understanding is correct... the capacitor like symbol is in fact contacts..1 normally open and 1 normally closed, commonly known as a changeover contact, as you will be able to determine by putting your meter on resistance across it.
Looks like capacitors to me too, (didn't know the symbols had changed). Re the other "capacitor" with the line through it, does the line end in an arrow or a little straight line? If an arrow it is variable if it is a little line it is "trimmable" i.e set (varied) when the circuit is first made/tuned then pretty much left.
Wiki agrees with me (mind you that doesn't mean a lot).
The symbols are completely non-standard but the connections for defrost timers are reasonably well standardised. Have a look here:
This particular model defrosts every 8 hours for 20 minutes, just like it says on the tin. Other manufacturers replacements should just slot in so long as the spec is the same eg. Frigidaire 5300628518 or Maytag 68233-2.
1 to 2 is Normally open 1 to 4 is normally closed.
Just because they are obsolete, does not always make them incorrect. So what are the symbols for capacitors and logic gates now? the vertical bars are usually associated with relay contacts and are normally numbered as to which contact pair and which relay.
In message , Vernon writes
They are no longer acceptable symbols
Not that I agree with it, the symbols are no longer "symbolic"
The capacitor hasn't changed
Go and look them up yourself
The symbols on the OPs timer are a capacitor and a variable capacitor, not contacts. I do not have an explanation for why they are so drawn. The other photo shows contacts
In message , soup writes
The symbols are in the convention of "ladder logic" used for designing programs for PLCs (Programmable Logic Controllers).
Surely, in Johns link - Pin 3 = Neutral Pin 1 = Live Pin 2 = N/O contact Pin 4 = N/C contact
Thanks for that
OP
Many thanks
So - 2 = Heater 4= Compressor
Judging by the diagram that Calvin posted above, yes.
They are capacitors. The one with the line through it is a variable one.
A classic case, it would seem, of one group of 'designers' doing their own thing contrary to accepted symbolism - dare I say IT people trying their hand at electrical engineering?!
The capacitor (condenser) symbol has been a standard for decades :-)
Depends on which symbol set you are using ;-)
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