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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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Strange RF problem
I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? -- geoff |
#2
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Strange RF problem
raden explained :
I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
#3
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Strange RF problem
In message , Harry Bloomfield
writes raden explained : I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. Changed the pcb, checked the fan ctrl relay first swapped the fan over several times The fan works without generating RF when back at the factory It's only when it's in the boiler -- geoff |
#4
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Strange RF problem
"raden" wrote in message ... In message , Harry Bloomfield writes raden explained : I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. Changed the pcb, checked the fan ctrl relay first swapped the fan over several times The fan works without generating RF when back at the factory It's only when it's in the boiler When you test it back at the factory, is it installed in way similar to in the boiler? It could be that the bonding arrangements are different (eg the bonding in the troublesome boiler isn't so good) and the fan is marginal- OK in a well bonded installation but not in a marginally bonded one. -- 73 Brian www.g8osn.org.uk |
#5
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Strange RF problem
In message , Brian Reay
writes "raden" wrote in message ... In message , Harry Bloomfield writes raden explained : I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. Changed the pcb, checked the fan ctrl relay first swapped the fan over several times The fan works without generating RF when back at the factory It's only when it's in the boiler When you test it back at the factory, is it installed in way similar to in the boiler? It could be that the bonding arrangements are different In which case, the other fan I sent him should suffer from the same problem. The two fans are identical (FSVO of course). The wires coming of the fans are of the same construction and are fast into the connections to the coil. (eg the bonding in the troublesome boiler isn't so good) and the fan is marginal- OK in a well bonded installation but not in a marginally bonded one. To generate RF really requires a spark of some sort if it's coming from 50Hz. This would represent a loss which would present itself as a less efficient fan motor (I would think) and therefore would not activate the air pressure switch) It's a total mystery -- geoff |
#6
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Strange RF problem
"raden" wrote in message ... In message , Brian Reay writes "raden" wrote in message ... In message , Harry Bloomfield writes raden explained : I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. Changed the pcb, checked the fan ctrl relay first swapped the fan over several times The fan works without generating RF when back at the factory It's only when it's in the boiler When you test it back at the factory, is it installed in way similar to in the boiler? It could be that the bonding arrangements are different In which case, the other fan I sent him should suffer from the same problem. The two fans are identical (FSVO of course). The wires coming of the fans are of the same construction and are fast into the connections to the coil. (eg the bonding in the troublesome boiler isn't so good) and the fan is marginal- OK in a well bonded installation but not in a marginally bonded one. To generate RF really requires a spark of some sort if it's coming from 50Hz. This would represent a loss which would present itself as a less efficient fan motor (I would think) and therefore would not activate the air pressure switch) It's a total mystery -- geoff Have you tried a megger on the fan? |
#7
Posted to uk.d-i-y
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Strange RF problem
In message , James Salisbury
writes "raden" wrote in message ... In message , Brian Reay writes "raden" wrote in message ... In message , Harry Bloomfield writes raden explained : I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. Changed the pcb, checked the fan ctrl relay first swapped the fan over several times The fan works without generating RF when back at the factory It's only when it's in the boiler When you test it back at the factory, is it installed in way similar to in the boiler? It could be that the bonding arrangements are different In which case, the other fan I sent him should suffer from the same problem. The two fans are identical (FSVO of course). The wires coming of the fans are of the same construction and are fast into the connections to the coil. (eg the bonding in the troublesome boiler isn't so good) and the fan is marginal- OK in a well bonded installation but not in a marginally bonded one. To generate RF really requires a spark of some sort if it's coming from 50Hz. This would represent a loss which would present itself as a less efficient fan motor (I would think) and therefore would not activate the air pressure switch) It's a total mystery -- geoff Have you tried a megger on the fan? Funny you should say that - no good idea, I'll do that on Monday -- geoff |
#8
Posted to uk.d-i-y
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Strange RF problem
"raden" wrote in message ... In message , James Salisbury writes "raden" wrote in message ... In message , Brian Reay writes "raden" wrote in message ... In message , Harry Bloomfield writes raden explained : I sold someone a fan for his CH boiler a couple of months ago and he swears that it causes RF interference. I sent him another one which he says is OK. We've also changed his pcb for him (to eliminate the possibility of it being a relay problem Now given the fact that it's a shaded pole motor and the connections to it are sound (i.e. electrically, it's just a coil of wire) does anybody have an explanation ? None... Except the connections were not in fact tight, or a fault on the PCB. Changed the pcb, checked the fan ctrl relay first swapped the fan over several times The fan works without generating RF when back at the factory It's only when it's in the boiler When you test it back at the factory, is it installed in way similar to in the boiler? It could be that the bonding arrangements are different In which case, the other fan I sent him should suffer from the same problem. The two fans are identical (FSVO of course). The wires coming of the fans are of the same construction and are fast into the connections to the coil. (eg the bonding in the troublesome boiler isn't so good) and the fan is marginal- OK in a well bonded installation but not in a marginally bonded one. To generate RF really requires a spark of some sort if it's coming from 50Hz. This would represent a loss which would present itself as a less efficient fan motor (I would think) and therefore would not activate the air pressure switch) It's a total mystery -- geoff Have you tried a megger on the fan? Funny you should say that - no good idea, I'll do that on Monday -- geoff And the answer was? |
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