ELECTRIFICATION
PAGE 1 - ADDING AN ELECTRICAL SUCTION
UNIT
When I electrify a player I keep it intact as much as possible. That is to
say I try not to make any changes that cannot be undone in the future. Someone,
someday, will be able to restore it to its original condition. When adding an
electric suction pump some modifications are going to have to be made. Many
players just do not have room in the case for the foot pump and suction pump.
Usually in this case one of the accumulators, which add suction between petal
strokes and even out the suction throughout the playing, has to go or be
repositioned. Some times they can be mounted on the side of the case, connected
with nipples and hose, to the suction manifold. In some cases the electric
suction box can be located outside the case. I have in rare instances built a
special suction box to fit between the frame on the back of the piano. This
however is a tough job and damping the noise and vibration from the sound board
is critical. Most people want the suction pump inside, here is one solution that
may work in some instances. The span of the accumulator that has been removed
may have to be altered somewhat. I have piggy backed them, as in the
illustration, if the case is deep enough. Either recover them separately and
glue them together using a firm cardboard gasket or packing leather, or screw
them together and recover them as a unit. You will end up with no lost volume or
spring power. In some cases you may have to engineer one to fit in whatever
space is available.
As you can see it only takes a couple of extra inches in case depth to
fit this in.
This a schematic of a dual speed control setup I have used for years. The
control box is made from an appropriate plastic or wood project box as the
situation dictates.(less is more) In the project box are mounted two speed
control pots, w/suitable knobs, one for regulating the player volume and the one
for the rewind speed. A master on/off switch and a pushbutton start switch are
also located within. Also add an on light indicator. This box is fastened under
the front or under the side of the key bed. The only remote switch is located
under the key bed or on the foot pump and is affixed so as to be actuated by
either a lever or a stop on the play rewind linkage. This switches the control
from the volume speed to the rewind speed which are adjusted separately. The
rewind speed can be adjusted if needed for such things as old rolls which are
brittle, you can rewind at a snails pace if needed. Some extra long play rolls
may need a tweak to get them to rewind at a proper speed but generally once set
you need not bother with it. Here is how it plays out: You put your roll in and
push the play button, hold the button in until the paper covers the sensor holes
in the tracker bar. (I often use #1,#2,#87,#88 as sensors and tube them together
to the shutoff pneumatic.) Once the tracker bar is covered the shutoff pneumatic
is inactive and the switch attached to it feeds back and locks the shutoff relay
in the on position. The play control is governing the speed of the suction box
and volume of play. When the end of the roll is reached the sensor holes in the
tracker bar are uncovered and the shutoff pneumatic is closed activating the
shutoff switch, which momentarily opens the relay shutting down the suction
pump. Manually activate the rewind lever and push the start button. When the
rewind lever is activated it turns control of the suction pump over to the
rewind control on the control box and the roll is rewound at a speed that you
have chosen, not full blast. At the end of the rewind the sensor holes in the
tracker bar are once again uncovered and the player comes to a comfortable stop
ready for the next roll. (How many times did I use "when" oh well)
Click on image to enlarge
The following is a very simple motor control circuit which I have never had
any problems with. I mount the components on a circuit board, you can etch one
or just go to Radio Shack or somewhere and get a small universal project board.
I try to mount it in the suction box and take advantage of the airflow for
cooling. Get an inclosed relay and you can mount it right on the suction box
also. Mount your suction pump on an isolation pad, re-bond carpet pad works well
for isolation purposes. Hook up your hoses, wire it up and let her rip. (note:
cut any holes in your foot pump manifold before you rebuild the bellows and
accumulators so you can clean it out well. Otherwise some splinters or sawdust
may get in your one way valve, under your flap valves, or clog up the screen on
your suction pump)
Click on image to enlarge
???? QUESTIONS ????
GLUE CLAMP FOR PNEUMATICS
