This is a multi-part message in MIME format. ---------------------- multipart/mixed attachment Here's the second. ----- Original Message ----- From: "Carl Meyer" <cmpiano@attbi.com> To: <pianotech@ptg.org> Sent: Thursday, December 13, 2001 6:37 PM Subject: handicapped pedal actuator > I promised to give some info on pedal solenoids. Sorry to take so long. > > I have quite a few left over pedal solenoids from the pianocorder days. > There were two sizes. One was the standard and the other was a heavy duty > one for the vorsetser. A picture is attached. It has an air chamber for > damping the stroke that never worked too well. > > A possible design would be to use two telescoping tubes spring loaded to > put under the piano with a fork of some kind to prevent turning at the top > and a rubber crutch tip against the floor or carpet. The solenoid could be > mounted on that tube with hose clamps and be adjusted up and down to press > on the pedal. Lots of fooling around to get it to work. > > Now for the schematic of the one I built for a friend. Realize that this > was installed in the piano and was not transferable. > > First, input is 110 volts 60 hertz. F1 is a one amp slow blow fuse. BR1 > is a bridge rectifier, of maybe 600volts at 6 amps. R1 is 150 ohms at 50 > watts. and controls the hold in current after solenoid activation. R2 is 27 > ohms 2 watts and charges the capacitor C1 to full 180 volts before > activation. C1 is an electrolytic capacitor 220 uf at 200 volts. The > capacitor gives a surge sufficient to activate the solenoid and then filters > the dc current from R1. CR1 and R3 are just there across the solenoid to > prevent arcing and to bleed off the energy stored in the inductance of the > coil. R4 is just a bleeder to prevent shock after power is removed. Values > will need to be adjusted for each application. Solenoid may make a klunking > noise. Anyway, that's the basic idea. Lot's more engineering would need to > be done to make it practical. > > Feel free to ask me questions, privately if you like. > > Carl Meyer Assoc. PTG > Santa Clara, California > cmpiano@attbi.com > ---------------------- multipart/mixed attachment A non-text attachment was scrubbed... Name: schematic.jpg Type: image/jpeg Size: 14630 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/15/45/83/c9/schematic.jpg ---------------------- multipart/mixed attachment--
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