The electrical characteristics of the Burgess Micro Switch.
| Identifier | ExFiles\Box 168a\2\ img245 | |
| Date | 1st July 1936 guessed | |
| BURGESS MICRO SWITCH Electrical Characteristics of the Micro Switch Alternating Current — The rapid snap action of the contacts, the generous use of silver in both contacts to dissipate heat, and the size of the switch gap all make it possible for the Burgess Micro Switch to break large currents. Micro Switches carry U. S. Underwriters' Laboratories label and Canadian Hydro-Electric Power Commission approval No. 4442 on the following ratings: 10 amperes at 125 volts a.c. 5 amperes at 250 volts a.c. 3 amperes at 460 volts a.c. 2 amperes at 600 volts a.c. 1/2 horsepower motor — 125, 230, 460 volts a.c. On normally open contacts, motor starting currents should be limited to 20 amperes. However, the overload capacity of the Micro Switch is such that in an emergency it will carry indefinitely a current of 30 amperes — the full stalled rotor current of a 1/2 horsepower motor — and safely break the circuit if called upon to do so. Its normally closed contacts will handle a lamp load of 1000 watts at 110 or 220 volts. Normally open contacts should be limited to 3 amperes for lamp loads at 110 or 220 volts. Carries the Inspection Label of the Underwriters' Laboratories and the Canadian Hydro-Electric Power Commission Direct Current — While the Underwriters' label on Burgess Micro Switches covers alternating current ratings only, the switch can be adapted to many direct current applications by suitably protecting the contacts with condensers. For very light loads, a condenser directly across the contacts will serve. For heavier loads, Burgess has developed a special circuit (patent applied for) in which a double pole (Blue Top) switch is used. The load is connected to one contact and the condenser to the other, with a 20,000-ohm condenser discharging resistor. By this means, the following loads can be satisfactorily handled: Voltage Current Load Condenser 125 d.c. 15 amp non-inductive 1 mfd, 600 v 125 d.c. 10 amp inductive 1 mfd, 600 v 250 d.c. 7 amp non-inductive 1.5 mfd, 600 v 250 d.c. 5 amp inductive 1.5 mfd, 600 v Special direct current applications should be discussed with Burgess engineers, as there are many points which cannot be fully outlined here. BURGESS | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).