Robbins & Myers G30

[Andrew White]

My wife Valerie gave me a "fan gift card" for my birthday. She said I could buy any fan I wanted as long as I had money on the gift card. So, naturally, I used a portion of it on this absolutely enormous 30" Robbins & Myers G30. I am beyond thrilled. This is exactly what we needed in our 900 square foot house!

Without a doubt, best birthday ever. Thank you Valerie!

Now where am I going to install the new piers under the house to hold this thing up... 

[Andrew White]

Here's my 6' 2" dad for scale...

[Andrew White]

And of course the nameplate

[Stan Adams]

I have a great idea, give me that column long nose ceiling fan & you'll have plenty of room for this!

[Arjun Saini]

Holy cheese! That’s a giant fan 

[Andrew White]

17 hours ago, Stan Adams said:

I have a great idea, give me that column long nose ceiling fan & you'll have plenty of room for this!

Hm, you know, I'll have to sleep on it 😆 I really think the only thing that would look good in its place is an R+M Lollipop...

16 hours ago, Arjun Saini said:

Holy cheese! That’s a giant fan 

Yes its gigantic! It has a crazy loud motor whine on startup that sounds amazing. And, as you might imagine, it moves an outrageous amount of air. 

[Arjun Saini]

6 hours ago, Andrew White said:

 

Yes its gigantic! It has a crazy loud motor whine on startup that sounds amazing. And, as you might imagine, it moves an outrageous amount of air.  
 

 

seems like one ain’t enough. LOL 

[Tom Zapf]

OH PSHAW...THATS JUST A DESK FAN FOR THE JOLLY GREEN GIANT ...ENJOY! 

[Stan Adams]

This style of 30"ers is fairly scarce, Jay Bernard looked for a blade for his for quite sometime.

[Andrew White]

Interesting. I've never seen one myself, but that isn't saying too much. It's quite different from the similar looking Hunter ones. You got me hooked on these circulators Stan. Can't wait to find a nice cast aluminum blade fan.

[David Deloria]

Awesome fan. I have one too. I was able to enjoy it for about 45 minutes until I smelt burning. Since then, I've been looking locally for one with a good motor for a replacement. So far I have found three but none work and the windings were toasted on all of them. I'm hoping to get lucky one of these days because it's a sweet fan. I love the heavy metal industrial aesthetic. I wonder if it's a common issue with the g30's? 

 

[Ken McClead]

6 hours ago, David Deloria said:

Awesome fan. I have one too. I was able to enjoy it for about 45 minutes until I smelt burning. Since then, I've been looking locally for one with a good motor for a replacement. So far I have found three but none work and the windings were toasted on all of them. I'm hoping to get lucky one of these days because it's a sweet fan. I love the heavy metal industrial aesthetic. I wonder if it's a common issue with the g30's? 

 

Here is a motor I found on ebay that might work for you.  Robbins & Myers Hunter G3058 Electric  Motor 1/4HP 110-120V 1090/600RPM | eBay
https://www.ebay.com/itm/154140591512

 

[Andrew White]

10 hours ago, David Deloria said:

Awesome fan. I have one too. I was able to enjoy it for about 45 minutes until I smelt burning. Since then, I've been looking locally for one with a good motor for a replacement. So far I have found three but none work and the windings were toasted on all of them. I'm hoping to get lucky one of these days because it's a sweet fan. I love the heavy metal industrial aesthetic. I wonder if it's a common issue with the g30's? 

 

Do you remember what happened leading up to the failure? I wonder if it was a capacitor issue that made it get hot and fail, or if it was some other issue. I have yet to let the smoke out of a fan, thankfully. 🤞 

 

I like yours with the huge blades. Must be an earlier model.

[Stan Adams]

Most Hunters & R&Ms I have run into which were cooked, was due to a Levolier switch. When people bring them to me to wire for them, I refuse unless they allow me to trash that Levolier. The series/parallel motors (which some Hunters use) are not as susceptible, but those standard tap windings, yes, that switch will let the magic smoke out instantly.

[Andrew White]

Ah that makes sense. All my fans have been de-levoliered already. 👍 I guess the emersons survive because of the series/parallel setup. 

[David Deloria]

On 4/29/2022 at 5:11 AM, Ken McClead said:

Here is a motor I found on ebay that might work for you.  Robbins & Myers Hunter G3058 Electric  Motor 1/4HP 110-120V 1090/600RPM | eBay
https://www.ebay.com/itm/154140591512

 

Thanks for the link but $400 seems pretty steep. I like the fan but not that much lol. 

[Jim Kovar]

Hi, Andrew.

I dig the chevron
motif base.

IMO, would look cooler
painted, with raised
detail a different color.

[Andrew White]

Update:

Upon further investigation, this fan is cooked.

I received it from the previous owner wired REAL wrong. It started and "ran" on high, but it whined like crazy and it was clear that it was fighting itself. Low would spin once started but would not start on its own. It was clear that it was wired incorrectly because it had a 1PDT switch wired up, but I did not try to reverse engineer what they had done.  I did not personally run it very long in this state before realizing it was not working right (tens of seconds, tops) and I did not measure amperage.

I re-wired it with a 3pdt switch the way it is supposed to be wired (I'm 95% sure I did it correctly) and wow, it ran great! Lots of torque on start up on high and low, the whine completely gone, amp draw within spec, everything. Sounded almost exactly like my 30" Emerson on both speeds.

It ran well for 10 minutes on high, nice and cool to the touch, then all of a sudden it started whining real loud, slowed down by about 25%, and started drawing about 10 amps. I turned it off as soon as I noticed the change, but it was already pretty hot, almost too hot to touch for longer than a few seconds. I let it cool down, re-checked my wiring, and tried it again. Still pulled 10-ish amps on high, same whining sound. Strangely, low pulled around 2 amps or less, and it seemed to run okay. It probably ran for a minute or so in that state.

I took it all apart and discovered what I feared.. the varnish on one of the windings (I think the capacitor winding, correct me if you think differently) is flaking off. So, I think this motor is shorted internally and is only a few minutes from letting the smoke out.

Ugh.

I don't think I caused this, but I regret not turning it off sooner.

I guess I am hunt(er)ing for a new motor now.

[Mark Olson]

Yes, it is cooked. that is actually the run winding that burnt. I can rewind it if you want.

[Arjun Saini]

1 hour ago, Andrew White said:

Update:

Upon further investigation, this fan is cooked.

I received it from the previous owner wired REAL wrong. It started and "ran" on high, but it whined like crazy and it was clear that it was fighting itself. Low would spin once started but would not start on its own. It was clear that it was wired incorrectly because it had a 1PDT switch wired up, but I did not try to reverse engineer what they had done.  I did not personally run it very long in this state before realizing it was not working right (tens of seconds, tops) and I did not measure amperage.

I re-wired it with a 3pdt switch the way it is supposed to be wired (I'm 95% sure I did it correctly) and wow, it ran great! Lots of torque on start up on high and low, the whine completely gone, amp draw within spec, everything. Sounded almost exactly like my 30" Emerson on both speeds.

It ran well for 10 minutes on high, nice and cool to the touch, then all of a sudden it started whining real loud, slowed down by about 25%, and started drawing about 10 amps. I turned it off as soon as I noticed the change, but it was already pretty hot, almost too hot to touch for longer than a few seconds. I let it cool down, re-checked my wiring, and tried it again. Still pulled 10-ish amps on high, same whining sound. Strangely, low pulled around 2 amps or less, and it seemed to run okay. It probably ran for a minute or so in that state.

I took it all apart and discovered what I feared.. the varnish on one of the windings (I think the capacitor winding, correct me if you think differently) is flaking off. So, I think this motor is shorted internally and is only a few minutes from letting the smoke out.

Ugh.

I don't think I caused this, but I regret not turning it off sooner.

I guess I am hunt(er)ing for a new motor now.

Rip 🪦, time for a rewind!

[Andrew White]

1 hour ago, Mark Olson said:

Yes, it is cooked. that is actually the run winding that burnt. I can rewind it if you want.

Bummer, that's what I figured.

I suppose low "works" because the more functional of the two run windings limits the current when wired in series but all bets are off when they are hooked up in parallel! I suppose the capacitor winding is the thinner gauge wire underneath it then? Makes sense..more wraps = higher ohms.

Mark, I might take you up on the rewind. I had a half-baked thought of trying to rewind it myself, is it something that is possible to do or does it require specialized equipment? I have a nearly limitless amount of patience for fan-related challenges...

[Andrew White]

I took these ohm measurements off of the current setup before I knew it was cooked. Of little to no use, but possibly interesting

[Mark Olson]

Andrew, it does not require any special equipment to rewind the motor.

You will need to 'diagram' the motor. this is done by drawing a linear representation of the stator slots.

When you remove the old windings count the turns. Be aware of the fact that those windings are tapped, which means that leads are brought out at certain turns. Essentially, there are two sets of run windings per pole.

The first set of windings you pull out are the start windings. They are not tapped and they are of a smaller diameter

Measure the diameters of the wire used in the start windings and run windings.

Draw the wire representation in the slots of your diagram for both the start and run windings. You will note the number of slots the start windings are offset from the run windings. In most modern motors this offset will be even, but on some older motors, wound for one rotation, it is not.

You will get the same number of opportunities as your motor has poles to get the turns count, tap positions and how the wire lies in the slot to get this correct and exactness of counts is important, but not super critical. Just make the new coils as close to the old ones as possible.

A winding form can be as simple as four nails on a board. You will need several to be able to replicate the various coil sizes that your motor uses.

Slot liners need to be made. Examine the old ones to see how they are made. I have tried different methods of slot liner construction and materials, but my goto is 0.010" fishpaper. Cuff the ends, it will help them stay in place.

Now begin laying in the new coils. Patience is key. I bring all my wires out on the same side of the stator.

I will use the terminology start and finish to describe the coil leads.

When all the run windings are in you will have a lot of ends sticking out. Using a meter is advised, as a sanity check, when connecting the coils. On the concentric coil ends, do not connect the start of the innermost coil. Connect the finish of the inner coil to the start of the next coil, the finish of that coil to the start of the next coil, and so on for each pole. Now you have the start and finish of each pole sticking out, along with your speed taps connected similarly.

Do not connect the start of the first pole coils. connect the finish of the first pole to the finish of the next pole, the start of that pole to the start of the next, the finish of that pole to the finish of the next pole until you have only two ends per speed sticking out. Drink a beverage of your choice.

Now lay in the start windings. You may choose to put a separator liner between th start and run windings.

Connect the coils of the start windings similarly to the run windings.

Now you have two ends of each winding sticking out. How they are connected will determine the direction your motor turns. I use a short piece of large copper pipe suspended with fishing line and a swivel to check rotation.

Arbitrarily pick an end of the run and start, connect them as common, connect the other ends as well. Put power through a variac to your motor, suspend the copper pipe in the stator and turn the power up until the pipe begins to rotate. If rotation is backwards, switch up how you picked common.

Make your headwire connections, lash the windings down nice and neat, spray it with insulating varnish and bake it by trickling current through. Don't over amp your windings! Use a meter. Save yourself a bit of trouble and mask the I.D. and O.D. of the stator before varnishing it.

Congratulations! You just successfully rewound your first motor!

[Andrew White]

Mark, thank you for your reply! I have a couple questions:

How delicate is the varnish on new magnet wire? I watched a guy on youtube banging and prying on the windings with metal tools and it made me sick to my stomach, but to my utter amazement his rewind ended up working fine. Obviously I am going to be more gentle than that, but realistically how delicate do I need to be when laying new windings into the stator?

And can you explain the "copper pipe rotation checker"? Do you mean like this?

 

[Mark Olson]

The enamel is fairly tough. laying the coils in the slots can be quite trying, especially on a smaller motor. If a wire gets between a slot liner and the stator laminates it will most likely short, requiring a redo. I've had quite a few redos and it is frustrating, discouraging, and quite frankly, heartbreaking. Practice makes perfect!

It does not have to be a copper pipe, a large brass nut will work, as will a suitably sized round motor run capacitor. Practically any cylindrical metal object should work.