Mechanical Music Digest  Archives
You Are Not Logged In Login/Get New Account
Please Log In. Accounts are free!
Logged In users are granted additional features including a more current version of the Archives and a simplified process for submitting articles.
Home Archives Calendar Gallery Store Links Info
MMD > Archives > December 2012 > 2012.12.25 > 06Prev  Next


Replacement Motors for Electric Player Pianos
By Alan Douglas

Regarding protective devices for electric motors: nothing will protect
against the starting winding being energized for any longer than it
takes the motor to come up to speed.  A start winding is wound with
small-gauge wire in order to get enough turns into the given space, and
cannot carry current for more than a few seconds before it overheats.
No thermal device can react that fast even if it were attached right
next to the winding.  (There are thermal relays that can, but those are
wired in series with the winding and are sized for the motor's starting
current.  They don't detect the temperature of the motor).

I used to rewind motors in a small shop, in summers between my college
years.  I would guess that ten seconds of energizing is enough to smoke
the insulation on a start winding and char the insulation, and much
longer would raise the wire temperature to a red heat, easily enough to
ignite enamel insulation and the organic varnish used to keep the wires
in place.  In our rewinds we used glass-insulated wire for the start
winding that actually would withstand red heat, but I'm sure no piano
motor ever used that.

Alan Douglas


(Message sent Tue 25 Dec 2012, 19:55:09 GMT, from time zone GMT-0500.)

Key Words in Subject:  Electric, Motors, Pianos, Player, Replacement

Home    Archives    Calendar    Gallery    Store    Links    Info   


Enter text below to search the MMD Website with Google



CONTACT FORM: Click HERE to write to the editor, or to post a message about Mechanical Musical Instruments to the MMD

Unless otherwise noted, all opinions are those of the individual authors and may not represent those of the editors. Compilation copyright 1995-2024 by Jody Kravitz.

Please read our Republication Policy before copying information from or creating links to this web site.

Click HERE to contact the webmaster regarding problems with the website.

Please support publication of the MMD by donating online

Please Support Publication of the MMD with your Generous Donation

Pay via PayPal

No PayPal account required

                                     
Translate This Page