Champion No. 50 220V Blower Rheostat Help

[Phil Dwyer]

Hi Folks,

Some of you might remember me. I used to frequent these parts, but lost heart with the loss of the blueprints two years ago. Anyway, if any of you good people have some suggestions for me regarding setting up an old Champion No. 50 blower with a 220V brush-style motor I'd sure appreciate it. I searched and read through the forums and a number of threads, but I'm still somewhat confused. Here's what I have and think I know, perhaps you can set me straight.

Here's the blower and tag on the motor....


I've tried running the motor with 110V, but it's fairly wimpy. On-the-other-hand, 220V revs her up enough to blow the coke clear out of the firepot! I understand and appreciate the gate, valve and damper approaches to air management. That being said, I am committed to being able to control the motor itself too via a rheostat...and there lies the rub. I'm not sure what to spec out. All I know about the motor is it's 220V. I do not know what amperage and resistance the rheostat should be.

I scrounged a couple but they aren't cutting the mustard.

This Ohmite one at 50 ohmes and 2.45A doesn't vary the motor speed much at 110V and doesn't slow it down enough at 220V.


This Mac Lagan measures up to about 2K ohms. It controls the motor at 110V in the 90 to 100 range. It comes on around 90 and moves up to full 110V speed at 100. In other words, it uses a small portion of the winding. Does that mean it's too much resistance? Anyway, I think I may have fused the coil when hooked up to 220V, as the motor started just running at full bore after being hooked up for a bit.


So, can anyone help enlighten me as to tracking down a rheostat that can effectively manage this 220V motor from zero to full blast????

Thanks, Phil

[Pat Roy]

Not being very conversant with electrons, I would consult an electrical engineer or at the very least someone at the local electrical supply house. You really need to know the motor characteristics, how many horsepower the motor develops, amps etc. Also I would suspect that trying to run this motor at 110 volts is probably unhealthy for it.

[clinton]

well it does say variable speed so using a rheostat should be ok, probably going to be pricey, an air gate would be more practical

[Sam Thompson]

I've always found it helpful to set the motor speed and use an air gate as an on/off when I don't need the fire for a few minutes. Unless the air gate is fitted to square tube, it is very hard to get accurate control as the increase in the proportion of the pipe being blocked varies as the gate moves across a round hole.

[Walking Dog]

I'm an electrical engineer with a good track record in getting these sorts of motors to work. There are two good ways to approach this.

Use a 220-V circuit with a 220-V variable transformer (trade names include "Variac," "Adjust-a-Volt," "Powerstat," and others). These variable transformers are widely available in surplus and old equipment as speed controls or light dimmers, and although a bit expensive, are efficient and don't put out the heat a rheostat would. The current rating needs to be about 1 A or better, GUESSING at the motor size.

Use a rheostat with a current rating of at least 1 A (guessing at the motor size). Your experiments say that you need more than 50, but less than 2000 ohms. Maybe 200 or 500 ohms. These things are also available in some surplus outlets, if you look hard enough. To narrow this down, find a couple of fixed resistors in the 200-500 ohms neighborhood and try them. The value you want for the rheostat is the smallest resistor value that will slow the motor down to the minimum speed you would ever want. The rheostat may be marked with a power rating in the neighborhood of 100-200 W, but as you've discovered, the real test comes at almost full speed where the motor current is at its highest and only the last few turns of the rheostat element are in the circuit.

There is no harm in running the motor on low voltage PROVIDED it doesn't overheat. Overheating might occur due to the lack of cooling air when the motor is slow or stalled, but as long as it doesn't overheat, it won't be harmed.

You could also try an electronic type light dimmer (220-V). These may or may not work right with a motor, but it won't hurt to try, as long as there is no overheating.

On a motor this old, be sure the bearings are free, the brushes are good, and the commutator is clean and not scarred and pitted. Bad brushes/commutator may lead to the case where the motor will run, but the speed control is very poor.

Good luck.
(Roger)

[HWooldridge]

Roger hit all the high points on the rheostat but I'll add that WW Grainger sells a variable speed control that works well with a brush type fan. I don't have the p/n handy but you might want to visit an outlet store and talk to a counter person about it.

In addition, even at the lowest speed setting, my factory Buffalo blower will blow the coke out of the pot with the damper wide open so some type of air gate is a necessity with this size blower.

BTW, I was able to acquire my forge many years ago because the former owner had hooked up the 220v motor to a 110v cord and was subsequently unimpressed with the performance. He was quite certain there was something wrong with it so I quietly purchased the rig then went home and wired it correctly. It's been sitting in the same spot for the last 19 years and works like it was designed to... ;)

[ThomasPowers]

Lucky you! The previous owner of my large "RR" forge got around the 220 issue by hacksawing off the back bearing on the motor and sticking a pulley on the shaft so exposed and running that from a 110 motor...

[Phil Dwyer]

Thanks guys, I really appreciate your input!

This is a pretty old motor with cast iron housing and bronze bushings (no bearings). I've taken it apart and cleaned it up. The commutator contacts seem in pretty good shape. One of the brushes is cracked so I'm going to a rebuild shop tomorrow in hopes to get new brushes. That being said, it seems to be running fine. (Getting all the old iron blade fins on their cast iron arms adjusted to clear the inside of the blower housing walls is another story.)

The variable transformer idea opens another vista of possibilities, although finding 220V ones looks to be as challenging as finding 220V rheostats.

How does this one look?

RARE- VINTAGE ZENITH VARIABLE TRANSFORMER- TYPE 36Y

Input: 240 V 50-60 Hz

Output: 0-240 V @ 1.5 A

Serial No. 7749

* This unit was removed from an old piece of laboratory test equipment.

* It is a very sturdy unit, and in excellent condition.

* Dimensions are approximately 3 1/2" in diameter by 3 1/2" long, and it weighs in at about 4 1/2 lbs.

[Phil Dwyer]

Here are a couple that look interesting. It would be a lot easier to use 110V input than 220V. Could I do that and still get the 220V performance out of the blower with one of these variable transformers?

Brand new variable transformer, i.e., Variac. Input is single phase 110V AC, 60 Hz, output voltage can be adjusted from 0 to 250V AC. Maximum power rating is 500 VA, maximum current is 1A at 250V and 2.5A at 120V. Net Weight: 6.1 lbs. Dimension: 7.0" X 6.7" X 6.7"

________________________________________________________________________________

General Electric Transformer -- Model 9T92Y29

[Walking Dog]

Phil

The RARE- VINTAGE ZENITH VARIABLE TRANSFORMER- TYPE 36Y should work well on a 240-V circuit, if you are happy with the price.

The "Brand new variable transformer, i.e., Variac. Input is single phase 110V AC, 60 Hz, output voltage can be adjusted from 0 to 250V AC." will be fine with a 120-V input circuit. Should be easy to apply this one.

Another option, if you don't have a 240-V circuit, is to use the combination of a 120-V Variac with a 120/240 transformer, as long as the price is right.

Roger

[double_edge2]

i have a shelf with jars full of the magic smoke from several types of motors,
from when i started mucking around with triacs and speed controller circuits.
i might have the right model for you, but the technology may not yet be up to date for re-inserting the smoke. :blink: