The ZBTSD Series incorporates the features of the ZBTS Bypass-Isolation Switch with those of the ZTSD unit for transfer of large motor loads, transformers, uninterruptible power supplies (UPS) systems or load shedding to a neutral ''off'' position. In critical systems such as those of hospitals and airports, power cannot be interrupted for maintenance and testing of automatic transfer switches (ATSs). In such circumstances, a bypass-isolation switch is essential and often required by code. The GE Zenith Controls ZBTSD Series Delayed Transition Transfer/Bypass-Isolation Switch meets requirements for inspection and/or maintenance of the delayed transition transfer switch without power interruption. The ZBTSD Series incorporates the rugged construction of all our ZTS Series switches with a quick-make/quick-break manual load transfer handle and our control/interlock system, consisting of both mechanical and electrical interlocks. The bypass uses normal failure sensing and a time delay to start the engine automatically if a failure occurs when the ATS has been removed for service.
