Thumler's Model B Motor Replacement Suggestion
Feb 27, 2022 0:19:05 GMT -5
catskillrocks, hummingbirdstones, and 3 more like this
Post by holajonathan on Feb 27, 2022 0:19:05 GMT -5
If you ever need to replace the motor on a Thumler's Model B tumblers, I recommend against buying the factory replacement. The original motor is a Fasco shaded pole induction motor. It costs about $60-$70 + shipping, has sleeve bearings that require oiling (no ball bearings), has low start-up torque, and uses about 50 watts of power.
The Model B uses a standard 3.3" diameter frame HVAC motor with a 1/4" shaft. This is a common size motor, so you have tons of replacement options, many of which can be found cheap on Ebay.
I've recently had good luck with a DAYTON model # 20HN89 motor. It is a direct fit for the Model B.
The Dayton motor is a permanent split capacitor (PSC) motor that spins at 1550 RPM, just like the original motor. I got one for $18 shipped on Ebay. It has sealed ball bearings which require no oiling. It has better startup torque than a shaded pole motor. And it uses 34w of power, 1/3 less electricity than the original motor. (PSC induction motors are more efficient than shaded pole motors.) I believe that both are 1/50 hp output.
Here it is running on a Rebel 17 tumbler, which is sort of like an upgraded Model B. Any motor that fits this tumbler fits the Model B. It is spinning a heavy load of Montana agates with no drama. It gets pretty warm since it is not fan cooled, but no hotter than the original shaded pole motor. It is continuous duty rated and should last many years if run nonstop. I've had it running or a few weeks without issue.
I bought the motor to slow down the tumbler speed, since this tumbler originally had a high speed 3000 rpm motor -- too fast for some rocks. But if you have a Model B that you run a lot, it might be worth upgrading just for the electricity savings. Every week, this motor will use around $1 in electricity, vs. $1.50 with the original shaded pole motor. After about 8.5 months, it would pay for itself on that basis alone, since I only paid $18 for it.
Here is a watt meter showing that it uses 34 watts.
If anyone thinks this is a bad idea for some reason, please let me know! I'm a tinkerer but not an electrician or AC motor expert.
The Model B uses a standard 3.3" diameter frame HVAC motor with a 1/4" shaft. This is a common size motor, so you have tons of replacement options, many of which can be found cheap on Ebay.
I've recently had good luck with a DAYTON model # 20HN89 motor. It is a direct fit for the Model B.
The Dayton motor is a permanent split capacitor (PSC) motor that spins at 1550 RPM, just like the original motor. I got one for $18 shipped on Ebay. It has sealed ball bearings which require no oiling. It has better startup torque than a shaded pole motor. And it uses 34w of power, 1/3 less electricity than the original motor. (PSC induction motors are more efficient than shaded pole motors.) I believe that both are 1/50 hp output.
Here it is running on a Rebel 17 tumbler, which is sort of like an upgraded Model B. Any motor that fits this tumbler fits the Model B. It is spinning a heavy load of Montana agates with no drama. It gets pretty warm since it is not fan cooled, but no hotter than the original shaded pole motor. It is continuous duty rated and should last many years if run nonstop. I've had it running or a few weeks without issue.
I bought the motor to slow down the tumbler speed, since this tumbler originally had a high speed 3000 rpm motor -- too fast for some rocks. But if you have a Model B that you run a lot, it might be worth upgrading just for the electricity savings. Every week, this motor will use around $1 in electricity, vs. $1.50 with the original shaded pole motor. After about 8.5 months, it would pay for itself on that basis alone, since I only paid $18 for it.
Here is a watt meter showing that it uses 34 watts.
If anyone thinks this is a bad idea for some reason, please let me know! I'm a tinkerer but not an electrician or AC motor expert.