. Electric railway journal . weight of the ammeter A is direct reading, and for ordinarytesting should have a scale reading 500 amp. The pro-tective circuit breaker D should be set sufficiently highso as not to blow while the test breaker is being ad-justed while still providing a safeguard against abnor-mal currents and short-circuits. If an ammeter witha full scale reading of 500 amp is used, the protectivecircuit breaker should be set to blow at about 400 double-throw switch S enables the same apparatusto be used for testing breakers either on or off the car,and should
. Electric railway journal . weight of the ammeter A is direct reading, and for ordinarytesting should have a scale reading 500 amp. The pro-tective circuit breaker D should be set sufficiently highso as not to blow while the test breaker is being ad-justed while still providing a safeguard against abnor-mal currents and short-circuits. If an ammeter witha full scale reading of 500 amp is used, the protectivecircuit breaker should be set to blow at about 400 double-throw switch S enables the same apparatusto be used for testing breakers either on or off the car,and should have the contacts so arranged that the ful-crum will not carry current. When it is thrown to theclown position the circuit is closed for testing break-ers on the car, and when in the up position breakersmay be adjusted in the rack P, which is arranged toclamp the breaker in the same position as when on acar. An insulated cable about 40 ft. or 50 ft. long isrequired for testing breakers on the cars, and the reel Trolley Wire. Fig. 1—Stationary Test Set with Water Rheostat andAmmeter R affords an effective and easy means of keeping thisoff the floor and out of the way when not in use. Aslip ring C with a brush contact is provided at one endso that the turning of the reel does not disturb theconnections. To test a circuit breaker on the car, remove the leadconnecting the circuit breaker with the controller andinsert the test lead K from the reel in its place. Closethe circuit breakers B and D and then put the trolleypole of the car on the wire. Then by lowering the elec-trode G into the water of the water rheostat, a circuitis created from the trolley pole through the circuitbreaker B on test, out the lead K and through thereel R to the switch S, through this switch, the circuitbreaker D, ammeter A and the water rheostat toground. By lowering and raising the electrode G anydesired current range may be obtained. To test circuit breakers off the car, place them in therack P and a
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