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Exchange magnets
Posted: January 6th, 2021, 8:39 am
by RicardoRQ
Hi guys!
I need to exchange the flywheel magnets, some advice?
I thought to drill in the exacly same places where stay the original magnets. If necessary, i will put some epoxy adhesive to hold the new magnets in right place. I found Neodymium (N35) magnets with 2,5 mm diameter, 1 mm height. Could these magnets too powerfull in this case?
Thanks in advance
Re: Exchange magnets
Posted: January 6th, 2021, 9:51 am
by c2jonw
is this a model B or C with three small magnets imbedded in the flywheel? If so, no need to drill- drive the old magnets out from the opposite side and get the proper magnets from C2. Note that polarity direction is important!
Re: Exchange magnets
Posted: January 6th, 2021, 11:00 am
by RicardoRQ
Thanks for the reply c2jonw.
This is a model B.Well, it's not so easy buy the proper magnets from C2 when you live in Latin America. The local dealer (in Brazil) sales only new machines, not parts. I don't have many options in this case, i must adapt something.
Could I damage de pickup sensor if put the magnets that i can buy here?
Thanks
Re: Exchange magnets
Posted: January 6th, 2021, 11:33 am
by c2jonw
It's unlikely you'll harm the sensor. Why are you replacing the magnets? The original magnets were rare earth measuring about .1" diameter x .1 thick so the one you have mentioned might work just fine. Glue them in place if needed. Note the polarity has to be the same direction as the originals.
Re: Exchange magnets
Posted: January 6th, 2021, 12:34 pm
by RicardoRQ
Because I put a new sensor and a new PM5 monitor that a friend brought me from USA. If I knew that the magnets was the problem I would buy togheter with the sensor and monitor. The second reason is that the flywheel (the steel plate) was sand blasted and repainting. In the painting process the piece was subjected to high temperature.
The result is that de monitor show a very high values. It seems like only one or two magnets work.
Well I'm going to adapt the new magnets and come back to show the result.
I really apreciate your help.
Thanks
Re: Exchange magnets
Posted: January 6th, 2021, 2:27 pm
by mict450
c2jonw wrote: ↑January 6th, 2021, 11:33 am
It's unlikely you'll harm the sensor. Why are you replacing the magnets? The original magnets were rare earth measuring about .1" diameter x .1 thick so the one you have mentioned might work just fine. Glue them in place if needed. Note the polarity has to be the same direction as the originals.
This is an interesting discussion on the inner workings of the C2.
Which pole, N or S, needs to face the sensor? Is the magnet itself, inscribed with the polarity? If not, would a magnetic compass dial diagnose polarity?
What would happen if 2 magnets were correctly positioned & one was not? Would watts be decreased by 1/3rd? 2 magnets placed incorrectly, watts decreased by 2/3rds? 3 placed incorrectly, would the PM even power up? Would drag factor, stroke count & drive time be affected by improper polarity position? I'm guessing they wouldn't be?
Re: Exchange magnets
Posted: January 6th, 2021, 2:34 pm
by faach1
mict450 wrote: ↑January 6th, 2021, 2:27 pm
c2jonw wrote: ↑January 6th, 2021, 11:33 am
It's unlikely you'll harm the sensor. Why are you replacing the magnets? The original magnets were rare earth measuring about .1" diameter x .1 thick so the one you have mentioned might work just fine. Glue them in place if needed. Note the polarity has to be the same direction as the originals.
This is an interesting discussion on the inner workings of the C2.
Which pole, N or S, needs to face the sensor? Is the magnet itself, inscribed with the polarity? If not, would a magnetic compass dial diagnose polarity?
What would happen if 2 magnets were correctly positioned & one was not? Would watts be decreased by 1/3rd? 2 magnets placed incorrectly, watts decreased by 2/3rds? 3 placed incorrectly, would the PM even power up? Would drag factor, stroke count & drive time be affected by improper polarity position? I'm guessing they wouldn't be?
I’d be very interested to see what someone like Jon says about this. I’d assume it wouldn’t make any difference although I’m no expert.
Re: Exchange magnets
Posted: January 6th, 2021, 2:43 pm
by mict450
RicardoRQ wrote: ↑January 6th, 2021, 12:34 pm
Because I put a new sensor and a new PM5 monitor that a friend brought me from USA. If I knew that the magnets was the problem I would buy togheter with the sensor and monitor. The second reason is that the flywheel (the steel plate) was sand blasted and repainting. In the painting process the piece was subjected to high temperature.
The result is that de monitor show a very high values. It seems like only one or two magnets work.
Well I'm going to adapt the new magnets and come back to show the result.
I really apreciate your help.
Thanks
This also, is interesting! I would guess if the magnets were subjected to sandblasting & heating (powder coating??) the PM wouldn't even power up.
Ricardo, when you say the readings are very high, are you referring to the splits? Eg: you were pulling 2:00 min UT2 splits before & now can't go below 3:00?
Re: Exchange magnets
Posted: January 6th, 2021, 3:16 pm
by c2jonw
Ricardo- Is the new monitor set for a model B/C? If it's set for a model D/E or something else it would explain the bad values you are getting.
The Model Type is a hidden function on the PM5. I believe you go to Main Menu/utilities/more utilities/lcd contrast. Then press the UNITS button 3 times, then press the DISPLAY button 3 times. I think this will bring you to the Model Type page where you can toggle to the B/C setting.
Re: Exchange magnets
Posted: January 6th, 2021, 6:05 pm
by Carl Watts
Cannot get the imperial size magnets in most parts of the world as we have all gone Metric.
If you gently tap the magnets with a punch they will disintegrate if they are faulty. If the nickel plating of the magnet gets compromised they oxidise and disintegrate.
I re-drilled the holes out to 3.0mm and replaced the magnets with Neodymium 3 x 4mm.
This is for the Model C, not sure what size the magnets are for the Model B, probably the same.
Its pretty rare for the magnets to fail but in very high humidity countries, rust on the Model C is pretty bad. I have replaced the magnets on only three rowers over the years.
Re: Exchange magnets
Posted: January 6th, 2021, 8:26 pm
by RicardoRQ
mict450 wrote: ↑January 6th, 2021, 2:43 pm
RicardoRQ wrote: ↑January 6th, 2021, 12:34 pm
Because I put a new sensor and a new PM5 monitor that a friend brought me from USA. If I knew that the magnets was the problem I would buy togheter with the sensor and monitor. The second reason is that the flywheel (the steel plate) was sand blasted and repainting. In the painting process the piece was subjected to high temperature.
The result is that de monitor show a very high values. It seems like only one or two magnets work.
Well I'm going to adapt the new magnets and come back to show the result.
I really apreciate your help.
Thanks
This also, is interesting! I would guess if the magnets were subjected to sandblasting & heating (powder coating??) the PM wouldn't even power up.
Ricardo, when you say the readings are very high, are you referring to the splits? Eg: you were pulling 2:00 min UT2 splits before & now can't go below 3:00?
Yes, powder coating.
There are 3 magnets, if one of them fail, the monitor shows that you are slower. One turn of flywheel is equal three pulses on the sensor. If flywheel has only 2, it need to roll more than one turn to show the same value.
In my case when I am pulling 2:00 min/500m, the monitor shows values upper than 4:00.
Re: Exchange magnets
Posted: January 6th, 2021, 8:34 pm
by RicardoRQ
c2jonw wrote: ↑January 6th, 2021, 3:16 pm
Ricardo- Is the new monitor set for a model B/C? If it's set for a model D/E or something else it would explain the bad values you are getting.
The Model Type is a hidden function on the PM5. I believe you go to Main Menu/utilities/more utilities/lcd contrast. Then press the UNITS button 3 times, then press the DISPLAY button 3 times. I think this will bring you to the Model Type page where you can toggle to the B/C setting.
In the version of PM5 that I bought, the selection of model is no more a hidden function. It's very easy to select the right model.
Re: Exchange magnets
Posted: January 6th, 2021, 8:43 pm
by RicardoRQ
Carl Watts wrote: ↑January 6th, 2021, 6:05 pm
Cannot get the imperial size magnets in most parts of the world as we have all gone Metric.
If you gently tap the magnets with a punch they will disintegrate if they are faulty. If the nickel plating of the magnet gets compromised they oxidise and disintegrate.
I re-drilled the holes out to 3.0mm and replaced the magnets with Neodymium 3 x 4mm.
This is for the Model C, not sure what size the magnets are for the Model B, probably the same.
Its pretty rare for the magnets to fail but in very high humidity countries, rust on the Model C is pretty bad. I have replaced the magnets on only three rowers over the years.
Carl, thank you for your report. Probably my machine will work soon!
Re: Exchange magnets
Posted: January 6th, 2021, 10:19 pm
by Ombrax
I can already see the wheels turning in people's heads: "Maybe if I add a few magnets..."
It sounds like the OP is on his way to having a working rower - Good Luck, and have "fun."
Re: Exchange magnets
Posted: January 6th, 2021, 10:45 pm
by mict450
Ombrax wrote: ↑January 6th, 2021, 10:19 pm
I can already see the wheels turning in people's heads: "Maybe if I
add a few magnets..."
That's probably why Concept 2 changed the flywheel for the Model D & E. I'm assuming the same flywheel is also used on the skierg & bike erg.