| 摘要 |
There is provided an emergency motor shut off for a closed air system having a low pressure threshold and a high pressure threshold. In a preferred embodiment, the closed air system includes a compressor and motor for charging the pressure of the system. Typically, any suitable electric power source provides power to the motor. A pair of electric contactorss electrically disposed between the power source and the motor are pneumatically controlled to allow electric current to either pass through or to prevent current from reaching the motor. A timer determines the run time for a single run cycle of the motor. A shut off that is responsive to the timer impedes the flow of electric current to the motor after a predetermined amount of run time. The timer is reset to zero after each run cycle of the motor. Typically the shut off comprises a relay timer having an internal relay. The invention also provides for an alarm to signal when the system when the predetermined amount of time is reached on the timer.
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