. Electric railway journal . will remainshut down until the series coil has cooled off enough toindicate that it is again safe to start. When the series relays operate and open the con-tactors, thus putting the main resistors in circuit, thegrids will become very hot if the short circuit or the ex-treme overload persists. A thermostat is mounted overthe resistance grids and when a dangerous temperaturehas been attained this shuts down the station until thegrids cool down. Overspeed Protection.—The usual centrifugal over-speed device is used on the machine and this is non-re-setting. In case of
. Electric railway journal . will remainshut down until the series coil has cooled off enough toindicate that it is again safe to start. When the series relays operate and open the con-tactors, thus putting the main resistors in circuit, thegrids will become very hot if the short circuit or the ex-treme overload persists. A thermostat is mounted overthe resistance grids and when a dangerous temperaturehas been attained this shuts down the station until thegrids cool down. Overspeed Protection.—The usual centrifugal over-speed device is used on the machine and this is non-re-setting. In case of overspeeds sufficient to trip the de- vice automatically the station must be visited by an in-spector to reset the trigger and permit further oper-ations. Bearing Protection.—The machine bearings are pro-tected against overheating by thermostats consisting ofcopper bulbs inserted in holes drilled through the sideof the pedestal into the bearing housing, the bulb con-necting with the copper bellows by copper tubing. The.
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