02-05-04 02:15
No 486462
Is it just antibody or have other bees noticed that their mag stirrers slowly lose RPM's as well as torque over time. If this is the case (and not an illusion) does anybee know why? And is the problem fixable?
We are all just witnesses.
(Newbee)
02-05-04 05:18
No 486491
Depending on the stirrer.." but IMHO the motor maybe fucking up, for example the wrapping on the motor is loosing its tension and therefore doesnt' create the proper magnetic nrg to maintain maximum RPM or, if in some cases the stirrer relies on a pully system then perhaps the pully is no longer doing its job.. as the tension of the pully from point A to point B is loose.
This maybe the prob.. so 1) the wrapping of wire on the inner motor is fucked and needs to be re-wrapped, or 2) the belt on the pullies is also loose.
I dont know if this will help, but if it does then great, i suggest pulling the stirrer appart no harm in that.."
(Hive Bee)
02-05-04 18:03
No 486603
it's more than likely worn brushes or dirty whatever you call em where brushes are being pushed against on the rotor.
(esoteric)
02-05-04 20:23
No 486616
try that first.
while you are at it, check that the magnets are still in their proper place. Yeah check the windings and brushes,
if you have brushes:
The "feet" that support the unit on combo heaters and stirrers must be maintained at their proper height at least, as the circulation is necessary for keeping th motors from toasting out.
I resuscitated a Thermolyne and kept it from certain death by
putting unscrunched footies on it.
dwarfer
(Stranger)
02-06-04 01:17
No 486720
If ya got a lot of time and a hardware store with brass tube and rod and a random surplus store with moters and some creativity and some hella strong glue and some nuts and bolts and hard rubber washers you can do what SWINM will never do again.....A custom rebuild! with a moter so strong the mags jumped of and had to be reglued and now gets nervous every time its on for long......
just buy a new one
(Hive Bee)
02-06-04 17:00
No 486902
All of the mag stirrers I have taken apart have used brushless motors of one type or another, shaded pole induction motors in the majority of them, or DC brushless motors in the newer units. I have seen brush-type motors used on stirrers, but generally only the overhead types.
The probable cause of a slowdown would be dry bearings or congealed grease binding the motor armature. A careful dissasembly/cleaning/lube/reassembly should fix this. Another possibility would be that the stirrer magnets have lost their strength through mechanical shock or overheating, allowing a loss of coupling between the stirrer and the stir bar.
Ellis D. Tripp
(LinguisticBee)
02-07-04 03:29
No 487012
thanx for the feedback bees, much appreciated!!
Ab2
We are all just witnesses.
(Hive Bee)
02-07-04 19:40
No 487115
I bought a used old Thermolyne multi-stir which heated but would not stir. Both stirrer motors are connected by a cog belt which was brittle. I called the company (which more Bees ought to do) and requested the tech info/parts list. I oiled the motors, repeatedly over about a week, top and bottom, with the machine right side up and upside down. The new belt i ordered arrived a few days later and that stirrer has been my best friend for the last two years.
Originally I thought I might get one working stir motor at best, but TLC, 3-IN-ONE oil and a $20 part brought that stirrer back to life. It works better than the new one I bought as back up.
Anyway, dont give up. Oil those shafts!
02-08-04 06:14
(Rated as: hazardous)
(Stranger)
02-09-04 02:29
No 487389
Try cleaning it out. If it has a rheostat inside, clean that too.