Trane RT-SVX10C-EN specifications Voltage Supply and Voltage Imbalance

[ ] Observe the ABC and CBA phase indicator lights on the face of the sequencer. The ABC indicator light will glow if the phase is ABC. If the CBA indicator light glows, open the disconnect switch or circuit protection switch and reverse any two power wires.

[ ] Restore the main electrical power and recheck the phasing. If the phasing is correct, open the disconnect switch or circuit protection switch and remove the phase sequence indicator.

Voltage Supply and Voltage Imbalance

Voltage Supply

Electrical power to the unit must meet stringent require- ments for the unit to operate properly. Measure each leg (phase-to-phase) of the power supply. Each reading must fall within the utilization range stamped on the unit name- plate. If any of the readings do not fall within the proper tol- erances, notify the power company to correct this situation before operating the unit.

WARNING

Live Electrical Components!

During installation, testing, servicing and troubleshoot- ing of this product, it may be necessary to work with live electrical components. Have a qualified licensed electri- cian or other individual who has been properly trained in handling live electrical components perform these tasks. Failure to follow all electrical safety precautions when exposed to live electrical components could result in death or serious injury.

Unit Start-Up (Continued)

Voltage Imbalance

Excessive three phase voltage imbalance between phases will cause motors to overheat and eventually fail. The maxi- mum allowable voltage imbalance is 2%. Measure and record the voltage between phases 1, 2, and 3 and calcu- late the amount of imbalance as follows:

% Voltage Imbalance =	100 X AV - VD where;
		AV
AV (Average Voltage) =	Volt 1 + Volt 2 + Volt 3
	3

V1, V2, V3 = Line Voltage Readings

VD = Line Voltage reading that deviates the farthest from the average voltage.

Example: If the voltage readings of the supply power measured 221, 230, and 227, the average volts would be:

221 + 230 + 227 = 226 Avg.

3

VD (reading farthest from average) = 221

The percentage of Imbalance equals:

100 X 226 - 221 = 2.2%

226

The 2.2% imbalance in this example exceeds the maximum allowable imbalance of 2.0%. This much imbalance be- tween phases can equal as much as a 20% current imbal- ance with a resulting increase in motor winding tempera- tures that will decrease motor life. If the voltage imbalance is over 2%, notify the proper agencies to correct the voltage problem before operating this equipment.

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