Question about Electro MFG hassock style table fan

[Joseph Simonetti]

So I recently bought this fan on E-bay and Ive seen these before. this one from what I gather from a patent an ash tray on top. But what I'm having problems with is how the large ceramic resistors are supposed to be wired up inside the base to the motor and switch. Originally when I bought the fan there were 2 of them (still are) one is 193 Ohms the other has a tap. One side measures 50 Ohms the other 93 ohms but when I bought it the 50 Ohm winding was open and they had the motor attached in series to the 193 Ohm one and the open one was wired to the same place in common also in series but the center tap was taped up, and not connected. The fan had clearly been serviced by some one who used it. and Im not sure how these resistors are actually supposed to go. I also find it odd that the switch only has 2 on positions and a normally open when one might think it would have a position that feeds the motor full line voltage. So Im very confused and I dont want to mess with this thing much more untill I know more about it. and I also dont want to damage my repair to the tapped resistor. In addition to that I would like to know what to do about the unussual bearing it has on the bottom. a bushing and a singular ball bearing set in 2 concave features, one on the bottom of the shaft and one on the bottom of some type of service feature which seems to be packed with a little grease. Im assuming its supposed to use grease or some heavy lubricant but since Ive never seen this before Im curious about that, and does the upper lubrication port need something more heavy than say Marvel? Im sorry for the large amount of questions here but Ive never seen anything like what's inside this and I dont want to damage or hook it up wrong.

[Russ Huber]

1498395739495455000-D0076012 (storage.googleapis.com)

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[Joseph Simonetti]

The ad you found is interesting which I didn't manage to find yet. the patent diagrams above is one of several I managed to dig up among one that shows 2 of the described functions in the ad. but based on what Im seeing it looks like the switch is original and supposed to have 2 speeds. I did go through the descriptions of the patents including that one. and it dosnt so much mention the manner of speed control or its hook up. Does anyone have one of these so I could see the underside?

[Russ Huber]

Does it have a brushed universal (AC/DC) motor?

Vintage Electro Mfg. Co. Horizontal Blade Electric Fan Dusty and crusty Working | eBay

Edited June 20, 2024 by Russ Huber

[Russ Huber]

If you take the plate off the bottom does the motor have brushes, or is it a brushless AC induction motor?

[Joseph Simonetti]

its a brush motor thats why I figure it uses resistors instead of a choke coil/transformer. also that picture up there is actually the auction on ebay I bought like the exact fan thats here now I know so because I remember removing those feet to replace them with new ones a couple days ago and the philip's head screw.. But what I meant is I want to see the inside so I know how these things are supposed to go. But back to the motor I think its made to run off both AC and DC due to the layout. I have an old Star rite that has a stack of resistance elements for speed for low and med. I figure it works like that but since its only got 2 speeds there are only a number of ways this can be connected up. and right now I fixed it so that it has a kind of mid and low. because when I bought that fan one of the settings was no good because there was a broken wire on one of the resistors. So maybe the motor was never supposed to run with the full 110 for speed purposes? (not that it probably cant handle it) thats what Im trying to get at mostly along with what the proper wiring of these 2 wire wound ceramic resistors actually is.

[Russ Huber]

The patent description on page #2 number 95 states it is a brushed motor, but I wanted to make sure. What is the diameter of your fan blade?

[Joseph Simonetti]

measures to 9 inches

[Russ Huber]

11 minutes ago, Joseph Simonetti said:

measures to 9 inches

Perfect. You have a center off double throw switch for high or low speed. On the low-speed selection if you want you can bypass those old "get hot" resistors and use a modern 3+amp 400-1000 watt half wave diode for pennies on the dollar for low speed. You simply place the diode inline from the low speed setting on the switch to the motor. The diode should work with that small a motor and blade. It won't hurt anything. It slows the motor using pulsating DC current. The pulsating rectified current is so fast you or your motor won't know it. Diode polarity won't matter. 🙂

Edited June 20, 2024 by Russ Huber

[Russ Huber]

The diode will slow the motor down roughly 700 RPM. Enough that you will notice a difference.

[Russ Huber]

Here is one example of a source for diodes. You may find them cheaper elsewhere.  3amp 1000watt will put you well into the safe zone.

20 X 1N5408 IN5408 3A 1000V Rectifier Diode | eBay

[Joseph Simonetti]

I think I actually have a couple of those left in my workshop. but thank you for the idea on the diode method. If I cant figure anything out with these things. Il probably just grab that plastic drawer out and do what you suggested. 

[Joseph Simonetti]

right now I have those things wired up in a series paralelle circuit so that it cut down on current on one of the settings and it wasnt getting hot like it was when I fist messed with it. But chances are Il either figure out what it was like or just do what you suggested.

 

[Russ Huber]

It may come across as rocket science to those that are not familiar with it, but it actually the farthest thing from rocket science, and works well without generating resistance heat that the old resistors produce. The diode is in the fan out of sight and out of mind. In short, who is going to know there is a diode or resistor in your fan other than you. 🙂

The only catch is half wave diodes do their best work for slowing SMALL universal brushed motor fans down. For some reason they don't work well using them for this purpose on the larger 12" and 16" brush motor fans. 

Edited June 20, 2024 by Russ Huber

[Joseph Simonetti]

Il probably wind up doing that. I mean I understood the idea of using diodes for that purpose to start with but Id not have thought to use it with a fan motor. Also mine is more or less the same as that schematic you have up there. Thank you for the help though because I probably wouldn't have thought to try that on this thing. Also I for sure wouldn't have known the diameter issue you mentioned there. 

[Russ Huber]

9 minutes ago, Joseph Simonetti said:

"I understood the idea of using diodes for that purpose." 

"I probably wouldn't have thought to try that." 

When you make up your mind what you know and didn't know, give that diode a whirl and let us know the results. 🙂 I have used them to bypass a second speed rheostat on an 8" fan successfully. I can't see the extra inch on your 9" fan should make a difference.