omhs reading for fan of ariston genus 27 bffi plus
- Thread starter deafjam1
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Boys - calm down, calm down!
To try to answer the OPs orginal question .....
The impedance of an AC motor is a complex thing: its consists of a resistive component & an inductive component. When you measure with your DVM you are applying a DC voltage & hence you can only see the resistive component, which is due to the length of wire wound around the motor coil.
The inductive component only "exists" when the motor is presented with an AC supply since it is created by the back emf caused by the changing magnetic field. It is this component which sets up the magnetic field inside the motor allowing it to work.
It is possible that replacement motors, made by a different manufacturer, but suitable for the job, have a different coil configuration & hence use a different length of wire but still perform the same. These would give different answers when measured with a DVM.
Consider also, if your little motor did really have an impedance of the 35Ohms that you measured, when presented with 230V it would pull around 6.5A and hence require over 1500VA!! Thats a big fan for a boiler! It is the inductive component that throttles this back.
Trying to compare AC wound components by measuring with a DVM doesnt really give meaningful results. Sure, you can see if the winding is open circuit & hence definitately trashed ... but trying to compare on the actual value has very little meaning.
Adrian
To try to answer the OPs orginal question .....
The impedance of an AC motor is a complex thing: its consists of a resistive component & an inductive component. When you measure with your DVM you are applying a DC voltage & hence you can only see the resistive component, which is due to the length of wire wound around the motor coil.
The inductive component only "exists" when the motor is presented with an AC supply since it is created by the back emf caused by the changing magnetic field. It is this component which sets up the magnetic field inside the motor allowing it to work.
It is possible that replacement motors, made by a different manufacturer, but suitable for the job, have a different coil configuration & hence use a different length of wire but still perform the same. These would give different answers when measured with a DVM.
Consider also, if your little motor did really have an impedance of the 35Ohms that you measured, when presented with 230V it would pull around 6.5A and hence require over 1500VA!! Thats a big fan for a boiler! It is the inductive component that throttles this back.
Trying to compare AC wound components by measuring with a DVM doesnt really give meaningful results. Sure, you can see if the winding is open circuit & hence definitately trashed ... but trying to compare on the actual value has very little meaning.
Adrian
Don't get sucked in by Joe effin 90. He's a seasoned troll and deserves only to be ignored.
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There's only one guy around here that knows his stuff and that's Tony Glazier. The rest of you are in here hanging onto his shirt tails hoping to pick up a few tips and a bit of knowledge.
How many of you are time served gas fitters? None. Say no more eh? Most can attach a gas pipe and flue and that's as good as it gets.
You are glorified DIYers and you know that so that's why you start the insults flying.
Get over it guys.
How many of you are time served gas fitters? None. Say no more eh? Most can attach a gas pipe and flue and that's as good as it gets.
You are glorified DIYers and you know that so that's why you start the insults flying.
Get over it guys.
You still here Joe?
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Anyone who has read Tony's posts over the past few years (as I have) knows that he is way out in front of the rest of you in regard to diagnosis. Everything I know I've learned from Tony. Tony Glazier is a gas God.
All rise. Tony Glazier has entered the room.
All rise. Tony Glazier has entered the room.
That is just lies.
I have had to put right hundreds of dangerous and wrong installations carried out by plumbers. There's people on this forum, so called knowledgeable people who are actively encouraging using earth wires as live wires.
Lies
I doubt that , job we are on we had to get the sparky to remove 4 cables he cable tied to the gas pipe
So there isn't an electrician in this country who can wire a heating system?
If someone is cable tying cables to a gas pipe then they are not an electrician.
If someone is cable tying cables to a gas pipe then they are not an electrician.
Of course there is, most of the installations I work on were in part, wired by electricians, they don't always "understand" the systems though, but that's not to say that your average plumber would either
here's a couple of quotes
now I don't doubt either of you, I see it regularly myself from both sides
same as I see excellent stuff from both sides
some people are really good some aren't so
and some are good but req more training
that's a good example and I 100% agree with you ie earth wires should never ever be used for anything other than earth connections, whether over sleeved/marked or not, and for good reason
I hope you advised them "why not"
well no they may be, they may have qualifications falling out their backside, they're just pi55 poor at their job,
Oh and I'm not knocking sparkies either RF, I used to be one
Matt
I agree. In my experience those people tend to be called 'intruder alarm engineers'
<runs for cover ............
>
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