GE ZTX manual Turn In-Phase Monitor OFF

Control Interface (cont’d)

DANGER

HAZARDOUS VOLTAGE

(Can Cause Severe Injury or Death)

Turn OFF all power before installation, adjustment, or removal of transfer switch or any of its components.

In-Phase Monitor

ZTX ATS senses when the sources are as far out as 2 Hz or as close as .01Hz in frequency differential of each other and transfers the load to and from either source in-phase. If turned on, R50 In-Phase monitor tracks the frequency of both the Utility and Generator sources allowing a smooth, synchronous transfer of the load, which is especially beneficial where conveyors, pumps and other motor loads are involved. ZTX indicates it is waiting for the sources to synchronize by holding the Timer/In-Phase LED on. When both sources have syn- chronized, the ATS will transfer the Load (within 20° of each other, if sources are within 2Hz differential), and the Timer/In-Phase LED will turn off. If the sources fail to synchronize, after 1 minute, the controller will blink the Timer/In-Phase LED once, alerting the operator that the In-Phase monitor function can be bypassed by pressing the CANCEL key, causing an immediate trans- fer (see Cancel Key function). If the CANCEL key is not pressed, the ZTX will continue to wait for an in- Phase condition to occur.

In a typical ATS application, one source is on the utility and one source is a backup system such as a gas or diesel generator. Because sources have a slight frequency difference, sources come in and out of phase. If ZTX In-Phase Monitor is on, The ZTX ATS Controller monitors both sources and transfers the Load at the ideal time to minimize back-EMF conditions.

In the case of both sources coming from the same source, or, one configured as WYE and the other as DELTA, the frequency difference is fixed at the same frequency or fixed but 30 degrees out of phase.

In those cases, In-Phase Monitor can be turned off.

In-Phase Monitor is turned on as default from the factory. To turn In-Phase Monitor OFF or ON, take the following steps:

Turn In-Phase Monitor OFF:

1.Remove all power, (both S1 and S2) from the controller. Wait at least 20 seconds.

2.From the keypad, hold both the BYPASS and CANCEL keys down while energizing either source. If In-Phase Monitor was on, the Timer / In-phase LED will flash once for 1 second, then go out. The In-Phase Monitor is now off.

Turn In-Phase Monitor ON:

1.Remove all power, (both S1 and S2) from the controller. Wait at least 20 seconds.

2.From the keypad, hold both the BYPASS and CANCEL keys down while energizing either source. If In-Phase Monitor was off, the Timer/In-Phase LED will light and remain lit until the keys are released. The In-Phase Monitor is now on.

Timer / In-phase LED

Figure 9

■ 10 ZTX Operation and Maintenance Manual (72R-1000) GE Zenith Controls ■