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1945 Theatre Catalog, 4th Edition, Page 407 (383)

1945 Theatre Catalog, 4th Edition
1945 Theatre Catalog
1945 Theatre Catalog, 4th Edition, Page 407
Page 407

1945 Theatre Catalog, 4th Edition, Page 407

If metals show rust spots, act promptly, as rust is an index of deterioration. Clean the metal casing of your air-conditioning unit, inside and out, at least once a year. Clean all rust spots with a wire brush or steel wool. To prevent further rusting, apply a rust arrestive, and then paint the metal surfaces with a water-resistant, rust-resisting paint.


Equipment, which has a fan for circulating conditioned air, a compressor supplying the refrigeration, and a water pump, includes a motor for driving the unit. The motor should be kept in good condition, if power costs are to be kept at a minimum. To start and stOp motors, follow operating instructions supplied at the time installation of the equipment was made. Dirt and misplaced 011 are poison to insulation, wiring, and commutator. Before cleaning a motor, always shut off the current. Clean motor surfaces frequently with a dry cloth. Never use water or cleaning fluids. Internal parts should be cleaned by an electrician or serviceman. Motors require periodic oiling. Your instruction book, dealer, or serviceman will tell you what kind of oil to use, where to use it, and how often.

Direct-Current MotorkOn all directcurrent motors, be certain that brush pressures are correct on the commutator, and that the brushes work freely in their holders. The commutator itself and the slots between segments should be kept free and clean of grease and dirt. The surface of the commutator should be cleaned off with a canvas cloth. Carbon tetrachloride may also be used, if available, to clean the commutator.

The interior of the motor housing should be blown out frequently, preferably with an electric blower, to remove dust. Accumulations of oil, grease, or other foreign matter around the base should be cleaned off. All insulated motor leads need to be cleaned of any grease. When the housing or framework is uncomfortable to the touch, it is a sure sign that the motor is laboring with an overload. If the commutator is known to be clean, the brushes have the correct tension, and the like, and if the motor is still arcing, it is then time to call in an expert. .

A commutator, which is so Worn that its surface is untrue and is pitted, will often cause considerable arcing. If this condition exists, it would be advisable to call in a competent concern to remove the armature and have it expertly repaired.

The proper grade of oil or grease should be selected for each type of motor, recommended by your lubricant manufacturer or oil company. At least once a year, all lubricating oil should be drained from bearings and the oil wells and the bearings fiushed out with gasoline, to remove all injurious sediment. Make certain that the oil wells have been blown out to remove all traces of gasoline before putting in fresh lubricant.

All worn gear cases could be likewise treated. All bearings which are packed with grease, except where they are permanently sealed, should be likewise treated.

On sealed-sleeve type of bearings, there


is usually a felt washer placed in such a manner as to prevent oil from running out along the shaft. When this becomes saturated and deteriorated, have your service man replace it.

Alternating-Current Motors-Some alternating-current motors have commutators and some do not; some have clip rings and different types of brushes. However, the maintenance problem is the same as for direct-current motors. If a three-phase motor fails to come up to speed, and you have trouble in starting, check the fuses in each phase, as sometimes a fuse will blow in one phase and the other will operate. If motors need removing for repairs, do not clip the wires. Unsolder them, as cut leads may increase the repair cost. When a motor has rubber mountings to lessen vibration, these mountings must be kept clean. Oil weakens and destroys rubber and, due to the scarcity of rubber, extra precaution to preserve it should be taken.


Refrigerants are necessary to the me- chanical cooling system. Take care of the refrigerant charge you have, by preventing leaks and having leaks repaired promptly when they do occur. If the presence of oil around fittings or gaskets, or any change in the general operation of the machine indicates a possible leakage of the refrigerant, be sure to call your serviceman to avoid losing the

entire charge. When non-condensable gases are present in a refrigerant system, it will operate at higher pressures than it would if these gases were not present. Unnecessarin high pressures result in the compressor-being subject to higher bearing loads, higher discharge temperatures, increased wear on moving parts, and greater power consumption. Such non-condensable gases should be purged from the system.

Screens for Air Intakes

The interior of' air-conditioning units, evaporative condensers, and similar equipment is protected by screens placed over the air intakes. These protective screens should be free from papers and other refuse, so that air can enter without interference. Do not block the air intakes with furniture, boxes, or the like.

Spray Nozzles

Spray nozzles are used in humidifiers, dehumidifiers, and evaporative condensers. For efficient operation, the spray nozzle must be serviced at regular intervals. Clean each spray nozzle, so that the spray is uniform throughout for the maximum efficiency. Keep water clean, so that dirt is not present to cause wear and corrOsion in nozzles. Inspect nozzles periodically for cleaning frequency, and set up a cleaning schedule to suit the locality. A nozzle needs cleaning when its fiow of water is irregular or depleted.

EVAPORATIVE CONDENSERS are installed (as shown here) to conserve water used by air-conditioning systems. Use of this equipment will, when properly maintained, pay for itself in u short time through the savings in water costs. Besides maintaining this equipment with the same care given all water-using apparatus, care must be token that evaporative condensers - and water towers, too - are not exposed to the dangers of freezing.

1945 Theatre Catalog, 4th Edition, Page 407