Hi everyone, I was hoping somebody could help me identify what I’ve been referring to as the “science project”. If anybody can tell me what this is, what it’s for, what it’s called, or if it is just a science project, I would really appreciate it. Also if anybody knows if it’s worth anything that would be great too… It has an S. Smith & Sons Aero Engine Revolution Indicator Mark IVA No. 17.06IF Non-luminous 6-22 hundred RPM. Attached to it is a Westinghouse AC motor type CA, 1/20 HP, 1700 RPM, frame no. 343.
I was only able to find one reference to the Mark IVA, and it was in a museum. In their description it was stated that it was manufactured from 1916 to 1918.
Thanks for any help.
By: Creaking Door - 6th June 2018 at 13:35
So why the RPM gauge?
By: smirky - 6th June 2018 at 12:05
“surely that isn’t how power is fed to the motor?”
Yes, no the motor is a four pole induction motor (with a split phase starter) and squirrel cage rotor. The power is fed to the stator coils, there are no slip rings. Under normal circumstances the motor will run at a nearly constant 1700 rpm determined by the input frequency, the motor speed is not readily adjustable.
By: Creaking Door - 6th June 2018 at 09:21
Actually that makes more sense; both the motor and the RPM gauge seem pretty permanently attached to the rig!
What’s going on at the other end of the motor with that crude ‘commutator ring’ affair; surely that isn’t how power is fed to the motor?
Three contacts onto the ‘commutator ring’: two end contacts constantly in contact with the different ends of the ring and one central contact that alternates contact between the two ends of the ring. It seems to me that this is designed to generate very rapid switching between the two contacts at a controllable, and indicated, RPM? But for what reason?
By: smirky - 6th June 2018 at 08:41
I would say that it is a teaching aid to demonstrate the properites of the motor which happens to have used some surplus aircraft parts.
By: Creaking Door - 6th June 2018 at 08:20
I can only guess that it is a rig for testing either the motor or the RPM gauge?
By: JonnyDucati - 6th June 2018 at 08:00
Hi everyone, I tried posting this a over a month ago and for some reason it only just now got approved to be released to the forum. However, because it is so old at the time of release it doesn’t even show up in the forum… I’m hoping that replying to it will get it back in the action. So, if anyone actually sees it I would greatly appreciate any insight into what this could be. Thank you in advanced.
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May 4, 2018 at 4:11 am