magnet resistance
Any one know that the ohm valve should be across a brake magnet
Forum Discussion
RoyB wrote:
It will be roughly around 4 OHMS... BRAKE MAGNETS will draw 3AMPS DC current when a full 12VDC is applied to them...
WATTS-VOLTS-AMPS-OHMS Caculator
Keep in mind all of the BRAKE MAGNETS will be wired in parallel so that will have to be taken into account if you just throw a OHMS meter across one of them...
I would not want to unsolder or disconnect a BRAKE MAGNET just to measure it's coil resistance. That could create even more problems...
I use a Sears CLAMP-ON AMPMETER around the one DC cable feeding all of the Brakes and hit them with 12VDC. Then if I have a single axle (Two Wheels) it should read 6AMPS or 12AMPS for a dual axle (4 Wheels)...
My BRAKE MAGNET emit a faint audible tone noise when they are activated. Others will use a CAMPERS COMPASS up close to the BRAKE MAGNET and look for the needle deflection when 12VDC is applied.
When using this method be sure to MEASURE the VOLTAGE as well. Do not assume it is 12.0V. For the most accuracy the voltage at each magnet should be measured as they will all be slightly different, but this is usually not very easy.- My apologies if your already aware of this but even though they may measure correctly, they may be physically worn out. Occasionally we need to remove the drum and check the magnets wear indicator.
- It will be roughly around 4 OHMS... BRAKE MAGNETS will draw 3AMPS DC current when a full 12VDC is applied to them...
WATTS-VOLTS-AMPS-OHMS Caculator
Keep in mind all of the BRAKE MAGNETS will be wired in parallel so that will have to be taken into account if you just throw a OHMS meter across one of them...
I would not want to unsolder or disconnect a BRAKE MAGNET just to measure it's coil resistance. That could create even more problems...
I use a Sears CLAMP-ON AMPMETER around the one DC cable feeding all of the Brakes and hit them with 12VDC. Then if I have a single axle (Two Wheels) it should read 6AMPS or 12AMPS for a dual axle (4 Wheels)...
My BRAKE MAGNET emit a faint audible tone noise when they are activated. Others will use a CAMPERS COMPASS up close to the BRAKE MAGNET and look for the needle deflection when 12VDC is applied. - From a quick Google search:
7 inch brake magnet resistance should be 3.8-4.0 Ohms
10 and 12 inch brake magnets resistance should be 3.2-3.5 Ohms
Cheers!
