| Bob Engelhardt <BobEngelhardt@comcast.net>: Oct 13 09:04PM -0400 On 9/8/2018 12:27 PM, Bob Engelhardt wrote: > https://imgur.com/a/yiBcCit > It surprised me that the original connecting wire was steel. I don't > know why steel would be used, but it made soldering difficult. With it "fixed", it still sparked like crazy! It took a while, but I finally found a transformer that I could re-purpose as a growler. With that I discovered that the armature had shorted windings. Sigh. I took it as an opportunity to do something new: rewind an armature. There's a number of YouTube videos showing it and it doesn't seem too hard. First, I needed the parameters: size of wire, number of turns in each winding, and the connections of the windings to the commutator segments. It was easy on the videos - you just unwind the old and record the parameters. Not so on mine - the windings were potted with epoxy. With some careful destruction I got some of it unpotted, but not the connections to the commutator. So I trashed it. Part of the commutator connections problem was that there were jumpers from the commutator to the windings. Most (?) armatures have their windings loop around a lug on a commutator segment and continue. I.e., each lug is the start point of one winding and the end point of another. On mine there were 2 commutator segments per rotor slot; the jumper on one connected to a winding wire, but the jumper on the other connected to _2_ winding wires! How could there be 3 connections per slot? Bizarrely asymmetrical. I'm disappointed that it wasn't more doable. |
| tabbypurr@gmail.com: Oct 13 07:02PM -0700 On Sunday, 14 October 2018 02:04:13 UTC+1, Bob Engelhardt wrote: > to _2_ winding wires! How could there be 3 connections per slot? > Bizarrely asymmetrical. > I'm disappointed that it wasn't more doable. motors with partial short can be run in series with a 3kW heater - but not now. NT |
| "G. Paul Ziemba" <unp@ziemba.us>: Oct 13 09:52PM >One of >those thermal fuses is bad, but with no way of spot-welding a >replacement in place is there any practical way of fixing it? Yes. The retail bubble-packaged replacement thermal fuses I have seen (at, e.g., Fry's) come with small crimp rings. -- G. Paul Ziemba FreeBSD unix: 2:51PM up 94 days, 4:19, 14 users, load averages: 1.47, 1.13, 1.03 |
| "Percival P. Cassidy" <Nobody@NotMyISP.net>: Oct 13 09:17PM -0400 On 10/13/18 5:52 PM, G. Paul Ziemba wrote: >> replacement in place is there any practical way of fixing it? > Yes. The retail bubble-packaged replacement thermal fuses I have > seen (at, e.g., Fry's) come with small crimp rings. Ah, Fry's. Unfortunately, the stores are all about three hours from here, and shipping probably would be much more than the cost of the item. I've bought a Bunn thermal fuse "set" (two connected in "Y" configuration, but I need only one). Should be here Tuesday. I have some crimp connectors and some push-in connectors. Both with insulation rated to 105C, which should be OK. Perce |
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