. Electric railway journal . ent we had the co-operation of the manu-facturers of thermit who were, however, not over-sanguine as to the outcome. One advantage of the use of thermit did show up inthis experiment, namely, that, while the weld crackedaround the edges of the insert and did not make abond at this point, it did provide a solid foundationunder the insert. Inasmuch as the bond was not com-plete between insert and the casting, a rocking motionor movement occurred under traffic and this resultedin the breaking up of the insert itself. We had one case where a loose insert jumped outof t
. Electric railway journal . ent we had the co-operation of the manu-facturers of thermit who were, however, not over-sanguine as to the outcome. One advantage of the use of thermit did show up inthis experiment, namely, that, while the weld crackedaround the edges of the insert and did not make abond at this point, it did provide a solid foundationunder the insert. Inasmuch as the bond was not com-plete between insert and the casting, a rocking motionor movement occurred under traffic and this resultedin the breaking up of the insert itself. We had one case where a loose insert jumped outof the casting under a car and wedged in under the the power house or substation, or from a number ofother causes. In many cases the reversal of rotation of a motor,aside from the inconvenience it causes, is not a seriousmatter as the error can be corrected at the motorterminals. In other cases, however, serious consequencesmay result. The reversal of an elevator motor, for RESISTOR ■vWM 6 TO TRIP CIRCUIT UNDERVOLTAGETRIP COIL. CONNECTIONS FOR NEWTYPE OF REVERSEPHASE RELAY instance, might result in wrecking the machinery andloss of life. To protect motors against phase reversal the Westing-house Electric & Manufacturing Company has developeda reverse-phase relay. If a phase is reversed, if aphase fails, or if the voltage drops below 75 per centof normal, the relay contacts close and trip the circuit- 426 Electric Railway Journal Vol. 52, No. 10 breaker, either through a shunt-trip coil or by short-circuiting an undervoltage trip coil having a seriesreverse resistor. The relay operates on the induction principle. Whenproperly connected the torque holds the contacts openagainst the restraint of a spiral spring. On low volt-age the torque diminishes and the spring closes thecontacts. On reversal of phase connections the reversedtorque assists the spring in closing the contacts. Automatic Oil Can FillerPrevents Waste TO PREVENT the overflowing of oil, throughcarelessness or misjudgme
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