Redneck cement mixer fix!
Posted: Sun Jan 29, 2017 7:33 pm
Yesterday Patrick & I decided to fill a shallow hole in the barn floor (used to store my Land Rover projects, hence the LR content ).
I dragged my 40 year old cement mixer out of the bushes behind the garage at our old house, un-siezed the wheels so it would roll, and plugged it in at the new barn.
No problem - a bit noisy at first but some grease lathered on to the pinion and ring gear, and squirted into the nipples for the pinion drive, and it quietened down nicely
Just about to start the first mix and it wouldn't switch on!
I remembered that it always had a slightly dodgy on-off rocker switch on the side of the motor, so took the cover off and using a testing screwdriver found that the neutral wasn't switching.
So I sorted that and started the first mix.
Just about to pour the first mix and the motor started struggling and slowing down
Managed to tip the first load then looked at the motor - I assumed it might be bearings as it had been out in the elements for the last 20 years.
However, taking the belt off I found it spun freely, but was definitely running slow when plugged in, even without any load.
So what do you do when you've already started a pour, still have 450kg to go and no spare motor handy?
Easy - pull the pulley off the motor, fit an M12 bolt and nut through the pulley, fit it to a very old electric drill, and bungy said drill to the motor frame!
Ok, it turned the wrong way (1950s technology hadn't even thought about reversible drills!) and was slow (500rpm), but we managed the next 20 or so mixes with no problem.
The drill, full cast alloy case, didn't even get warm!
Checking the motor today, I suspected either a winding shorting out or the run capacitor failed.
Using my optical tacho, I found the motor was running at around 740rpm, about half of its rated speed.
I happened to have a spare capacitor from the industrial fan units which were in the ventilation roof turrets in the barn, so hooked that up in place of the original and it ran at 1475rpm.
It wasn't anywhere near the 10uF original, but seemed to do the trick for testing.
So now I've ordered a new capacitor and hopefully will have my faithful mixer mixing again next weekend
Cheers,
Robin.
I dragged my 40 year old cement mixer out of the bushes behind the garage at our old house, un-siezed the wheels so it would roll, and plugged it in at the new barn.
No problem - a bit noisy at first but some grease lathered on to the pinion and ring gear, and squirted into the nipples for the pinion drive, and it quietened down nicely
Just about to start the first mix and it wouldn't switch on!
I remembered that it always had a slightly dodgy on-off rocker switch on the side of the motor, so took the cover off and using a testing screwdriver found that the neutral wasn't switching.
So I sorted that and started the first mix.
Just about to pour the first mix and the motor started struggling and slowing down
Managed to tip the first load then looked at the motor - I assumed it might be bearings as it had been out in the elements for the last 20 years.
However, taking the belt off I found it spun freely, but was definitely running slow when plugged in, even without any load.
So what do you do when you've already started a pour, still have 450kg to go and no spare motor handy?
Easy - pull the pulley off the motor, fit an M12 bolt and nut through the pulley, fit it to a very old electric drill, and bungy said drill to the motor frame!
Ok, it turned the wrong way (1950s technology hadn't even thought about reversible drills!) and was slow (500rpm), but we managed the next 20 or so mixes with no problem.
The drill, full cast alloy case, didn't even get warm!
Checking the motor today, I suspected either a winding shorting out or the run capacitor failed.
Using my optical tacho, I found the motor was running at around 740rpm, about half of its rated speed.
I happened to have a spare capacitor from the industrial fan units which were in the ventilation roof turrets in the barn, so hooked that up in place of the original and it ran at 1475rpm.
It wasn't anywhere near the 10uF original, but seemed to do the trick for testing.
So now I've ordered a new capacitor and hopefully will have my faithful mixer mixing again next weekend
Cheers,
Robin.