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954 HANDBOOK OF PROJECTION FOR
or stopped — from as many different places in the theatre as may be desired. The device may be reversed or stopped at will. It is not necessary to stop the device before reversing. It has neither batteries, relays or contactor switches. The only switches used are standard three-way and four-way switches, hence, the liability of switch trouble is reduced to a minimum.
The motor journals have oil wells and oil rings instead of the journals being oiled by means of a wick. See figure 148, page 499.
The gear reduction train is ball bearing and is packed in hard grease, calculated to give very long service without attention.
The drive to the curtain is by means of a Y%f tiller rope (tiller rope has steel core with braided cotton covering) running in V pulleys, which provides maximum tractive power without slippage, together with minimum probability of trouble. Also it simplifies installation, as device does not have to be lined up so accurately with curtain sheaves.
The curtain may be instanly freed from the motor control device, so as to be operated by hand; also it may be instantly attached again when desired. In these operations it is impossible to get the curtain "out of time" with the device. You may detach and attach the control device at any desired point in the opening and closing operation and the control will still start and stop the curtain exactly at the right point. Slippage of rope does not affect points at which curtain will start or stop.
Weaver Bros, also make one style of control that mounts on the sloat, permitting the whole curtain to fly as well as the barn door effect, or both effects at once. This model is along the same general lines as the one described except, that it cannot be operated by hand, owing to its position on the sloat. All the parts possible are made from aluminum, instead of cast iron, in order to reduce weight. This model is becoming very popular because of the different effects that can be secured through its use.
WIRING.— The motor is specially wound, single phase, and has three terminals, No. 1, 2 and 3. No. 1 lead is the neutral wire and connects to stop circuit. No. 2 and 3 connect to breaker switches, which are in the reversing circuit. The stop circuit is no more than one side of the line run through a series of three-way and four-way switches, and the revers