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1954-55 Theatre Catalog, 12th Edition, Page 310 (274)

1954-55 Theatre Catalog, 12th Edition
1954-55 Theatre Catalog
1954-55 Theatre Catalog, 12th Edition, Page 310
Page 310

1954-55 Theatre Catalog, 12th Edition, Page 310

NOTE the over-sized components (above). The rectilier has thumb-thick glass insulation. The phplo (below) otters a view at the powerful 290 pound transformer ready to be installed in the rectifier.

Elfective Cooling. In these scientifically arranged forced-draft models, the stack size and cooling capacity are conservatively designed, permitting continuous full-load operation at any rectilier room temperature normally encountered.

Rugged Transformer

There is plenty of reserve power in the Class B-construction trarsformcrs. They will deliver their full rated output continuously, at high efiiciency and power factor. Insulated and vacuum-impregnated with heat and corrosion-proof

materials, these transformers have practically unlimited life.

Built-in protective circuits and controls guard against dangerous overloads and stack over-heating. The unusual use of a three-pole magnetic contractor switch serves to completdy isolate the equipment from the AC line; a safety precaution for the projectionist.

All that is necessary to install a Selectificr is to connect it to the AC line and to the DC arc, and the rectifier is ready to go at the touch of a button. Outputs of different units are easily combined in

series or parallel for greater capacity, if ever needed,


The impeller fan is mounted at the top, with cooling air feeding in from the side openings. The top is closed so that it does not matter if it is covered with storage items, as frequently occurs. The impeller blows cold clean air down over the stacks, in scientifically designed distribution, past the heavy transformers in the base section, and out through the base. No dirt is drawn in off the floor of the room, or can fill in from above.

All units are designed for continuous duty, to have long life and to be dependable in use, with the reserve capacity and ability to sustain temporary current overloads, should emergencies arise.

Arc current and voltages are easily controlled by top changing switches mounted on the unit, and accessible to the operator. Adjustments may be made while the lamp is on. In addition, because of the single moving part, there is almost a complete lack of maintenace, and any that is required is simple and infrequent.

Arc Voltage Control

To cure incorrect arc voltages, one of the most persistent causes of complaint concerning arc operationeseldom recognized as the actual causeethe voltage supplying the arc has been made variable with a high and low range, In addition, the usual input line voltage taps and also three heavy-duty tapped switches are mounted on the front panel, to make possible the in-use flexibility of adjustment which is required, due to the changing line voltages, during the program day. A movement of wrist gives the output desired .

Deluxe Features

Deluxe type units have many added features not found in the standard models. For instance, an alarm warning device is incorporated as an integral part of the assembly, and functions when the operating temperature of the rectifying elements exceeds a pre-determined, chosen maximum point. The alarm only serves to warn the operator, but in no way interrupts the power.

Ripple output of "50,000 hour,y Selectifiers is brought to a minimum by means of a special rectifying circuit whose construction is more complicated and costly, but allows for a 12-phase ripple, and therefore, truly flickerless light on the screen.

Rectifying element areas are increased (more stacks), which in turn increases the life and efficiency of the unit as compared to standard models. Enclosures for these units are made of steel, welded construction, and are attractive in appearance. Efficiency of these engineered units run as high as 85 per cent, resulting considerable savings in power.

The lack of moving parts, except for the impeller fan, makes the unit extremely quiet in ope 'ation as compared to motor generators.

Selectitier arc units are made in ranges of 50470 amperes, 70-90, 90-115, 110-140, 150-190, and 210-250 amperes, for 3-phase lines. For single phase a new model has added choke filter circuits to obtain normal 10w ripple output.

1954-55 Theatre Catalog, 12th Edition, Page 310