Thanks for all the replies.
It's possible it may have a short somewhere, some things my Grandad kept have proved to be knackered.
Quote:
Originally Posted by Radio Wrangler
There doesn't seem to be a housing on that motor for a centrifugal switch, nor for connections from an internal one.
1400rpm says it's a 4-pole induction motor. S & R say it's for single phase. So it either has a capacitor start/capacitor run arrangement, or it has a timed start.
There are no facilities for mounting a capacitor outside the connection box. With the windings hard-commoned there aren't facilities for reversing it, either.
It looks to have been damp. The bearings might be doubtful.
David
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As it's an enclosed motor it may well have been used outside, or stored badly over the years. If it was part of a ventilation/blower unit it may have been intended to be fixed rotation.
Quote:
Originally Posted by Lucien Nunes
Some random thoughts:
Keith Blackman made at least some of their motors in-house, not sure whether all. They were a large concern with multiple sites making all kinds of ventilation plant and ancillaries.
It's a totally-enclosed motor that might have been in the fan's airflow, in which case the capacitor (if required) might have been remotely located. That is about the only good reason for having three terminals. The resistance readings are indicative of a capacitor motor (or a 3-phase winding re-purposed as single-phase.) A traditional split-phase switch-start motor would typically have two windings of different resistance sharing a common terminal, hence giving three different resistance readings one of which is the sum of the other two. There is sufficient room for a centrifugal switch in the end bell, however the line current is low at 2A for a 1/3hp 240V motor, suggesting capacitor run.
Can you confirm the resistance (and if possible, inductance) readings and perhaps prove that they are a mesh of three similar coils?
On a different note, is that a Century RSIR motor I see in the background?
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Yes I can recheck the resistance and try measuring the inductance with one of the LCR bridges here (no idea how good the readings will be as none have been checked on inductance, I have decade boxes for checking R & C). This may have to wait till next weekend as it's raining.
And yes there is a Century repulsion start motor in the background, the spec plate is missing but it does have a plate for the sales agent "Swedish General Electric Ltd." which dates it to somewhere between 1915 & 1928 according to Graces Guide, it's also fairly rusty & caked in sawdust from being stored in the woodworking shed.
David