Jeff Gavel Posted July 29 Share Posted July 29 Good day all, I have this Emerson 77646-SL (1956) that I got in 2020. Cleaned, lubed, re-wired the power and she was good to go. Ran for the last 4 years fine, then suddenly slowed way down and now needs a manual assist to spin up. On the low setting it almost comes to a crawl. I keep her oiled all the time and only really ran it in the summer. This is a shaded pole (2 wire to head) so no capacitor. I've cleaned again and confirmed oil is flowing to the rotor shaft. Seems to spin ok and no significant resistance when spinning the rotor without the blade attached and needs an assist to spin with the rotor only too. I have also tried moving the washers behind and in front of the rotor, but no luck. One strange thing (to me), is the rotor is happy spinning clockwise (normal) and counter-clockwise with the same manual assist to spin. Any thoughts are appreciated. Jeff Quote Link to comment Share on other sites More sharing options...
Patrick Ray Posted July 29 Share Posted July 29 What oil are you using? Quote Link to comment Share on other sites More sharing options...
Rod Rogers Posted July 30 Share Posted July 30 Does it use a capacitor? ~Sparky~ Quote Link to comment Share on other sites More sharing options...
Lane Shirey Posted July 30 Share Posted July 30 9 hours ago, Rod Rogers said: Does it use a capacitor? ~Sparky~ He mentioned it’s a shaded pole. Quote Link to comment Share on other sites More sharing options...
Lane Shirey Posted July 30 Share Posted July 30 12 hours ago, Jeff Gavel said: Good day all, I have this Emerson 77646-SL (1956) that I got in 2020. Cleaned, lubed, re-wired the power and she was good to go. Ran for the last 4 years fine, then suddenly slowed way down and now needs a manual assist to spin up. On the low setting it almost comes to a crawl. I keep her oiled all the time and only really ran it in the summer. This is a shaded pole (2 wire to head) so no capacitor. I've cleaned again and confirmed oil is flowing to the rotor shaft. Seems to spin ok and no significant resistance when spinning the rotor without the blade attached and needs an assist to spin with the rotor only too. I have also tried moving the washers behind and in front of the rotor, but no luck. One strange thing (to me), is the rotor is happy spinning clockwise (normal) and counter-clockwise with the same manual assist to spin. Any thoughts are appreciated. Jeff Are you sure it’s a 2 wire shaded pole? I’ve never known a shaded pole motor to be able to run backwards, even with a push. It has permanent copper shading bands. Didn’t think that was possible. But I may be wrong. Quote Link to comment Share on other sites More sharing options...
Mark Olson Posted July 30 Share Posted July 30 The copper shade bands provide the initial impetus in the direction of rotation, after the motor is at speed the shade current is negligible in the dynamics of the motor operation. I suppose that spinning a shaded pole motor against it's normal starting direction could cause it to run backwards, but as Lane said, I've never seen that, either. All in all, without having the motor in hand, the symptoms described in the original post lean towards the bearings being worn as the cause. Can you share a picture of the motor? Quote Link to comment Share on other sites More sharing options...
Geoff Dunaway Posted July 30 Share Posted July 30 79646 would be a 2 lead shaded pole but I thought all 77xxx fans but for the 1937 models were capacitor driven. The history is compatable with a capacitlr going bad too. Take the base plate off & see if there is a sardine can style capacitor clipped to the base, or a metal clip that might have held a capacitor in the base. 77xxx fans are all with overlapping blades if I remember right. 1 Quote Link to comment Share on other sites More sharing options...
Jeff Gavel Posted July 30 Author Share Posted July 30 Using 3-1 Blue oil It turns out I was wrong on the Shaded Pole - This fan has 3 wires going to the head and is missing the capacitor. Someone must have re-wired and left out the sardine can capacitor (before I added a new power cord). I think I need this capacitor: 1.5 uf @ 400+ VAC a 12" Emerson PSC motor So... Any advice to confirm this capacitor rating and where to buy a good replacement? - I had bought a capacitor online before for another 77xxx series to replace the original capacitor, but the fan ran quite a bit slower. Thanks, Jeff Quote Link to comment Share on other sites More sharing options...
Lawrence Smith Posted July 30 Share Posted July 30 wow. it ran for 4 years like that, now you will need an ohm meter & ohm out the 3 wires going into the stator. pair them off, the highest pair is the start & run windings, the loose one is common, then take the common & pair with the other 2 leads, the highest of those 2 is the start or auxillary, the other is the run winding. now if you have good readings use a 1.75 mfd capacitor (1.8 or 1.5 is available 440 volt ebay cheap) the cap goes from the high speed tap to the stator, the run also goes to the high speed tap, the common is connected to one side of your line cord. done I usually jumper this to test before re assembly it's cumbersome but much easier than taking everythoing back apart. Quote Link to comment Share on other sites More sharing options...
Jeff Gavel Posted July 30 Author Share Posted July 30 Lawrence, Thanks for the detailed info to re-wire the capacitor. I have this image for wiring for a 77646-ASfrom the Tom Newcity site. Is this correct with your instructions? Quote Link to comment Share on other sites More sharing options...
Andrew Block Posted July 30 Share Posted July 30 Waaaaiiittttt.......isn't that a .90a model? If so, then it's shaded pole. I've had a few of these and none of them had a cap. At some point in the late 50's, Emerson switched the 12" over to shaded pole for cost reasons. The 16" retained it's capacitor until the bitter end. Quote Link to comment Share on other sites More sharing options...
Jeff Gavel Posted July 31 Author Share Posted July 31 Thanks Andew. Yes, this 77646-SL has a .90 amp rating and it a 1956 model. But still. there are 3 wires to the head. I appreciate your input. Quote Link to comment Share on other sites More sharing options...
Andrew Block Posted August 1 Share Posted August 1 Yeah, I believe they all had 3 wire headwires. Black/Red/Green. Here is a diagram from Tom N. 1 Quote Link to comment Share on other sites More sharing options...
Marc Sova Posted August 2 Share Posted August 2 Yeah….all the 77’s are awesome fans. Pretty much what I’ve but my teeth on as far as learning to work on fans. I have several. 77646 AS is my fav along with the AN. AS is my nighttime bedside fan. Quote Link to comment Share on other sites More sharing options...
Jeff Gavel Posted August 3 Author Share Posted August 3 Hey Marc, Yep - I got sucked into the Emersons when my grandfather's 77646-AS quit working.. After fixing that I started buying and had plenty of time to repair/restore during covid.. I think I have around 8 right now so I guess I've learned a little. Shaded Pole motors can have 3 wires. Thanks @Andrew Block for the -SL wiring diagram 1 Quote Link to comment Share on other sites More sharing options...
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