How do I hardwire an SRT10KRMTF and APTF10KT01 Step-Down Transformer in a 208/120 or 240/120 environment?
Issue:
The customer is asking how to hardwire an SRT10KRMTF or APTF10KT01 stepdown transformer to have a 120, 120/208, or 120/240 output.
Product Line:
Smart-UPS / Smart-UPS Online / SRT10KRMTF / APTF10KT01
Environment:
All Serial Numbers
Cause:
Unbalanced UPS outputs require a stepdown transformer to power 120v loads
Solution:
Note: This document refers to installing the SRT10KRMTF and APTF10KT01 transformers in a North American 120/240 or 120/208 environment only.
The wiring block outputs are as follows:
Please make sure that the Terminal Block Jumper is installed between the Ground Terminal and Terminal 8 on the output wiring block, as illustrated on page 9 of the User Manual. Please also make sure that the input voltage selector/switch is in the correct position.
The step-down transformer provides 240/120 output as 2 120v hots, a neutral, and a ground. It provides 208v output as a 120v hot, an 88v hot, and a ground. The 120v hot (terminal 7) and the 88v hot (terminal 9) are 180 degrees out of phase. You will measure 208v from terminals 7 to 9. The step-down transformer is not able to provide 2 120v hots that are 120 degrees out of phase as you would see with utility power.