Alpha Technologies BPT Series Bypass Transformer User Manual
Page 13
4 Operation
4.1 Testing Bypass Switch Operation
CAUTION: This test must first be performed with all power to the Bypass Switch turned
OFF..
To test that all connections are made correctly, with all power to the bypass switch turned off,
measure the resistance between pin 2 & 3, 5 & 7, and between 9 & 11 to ensure that there is
no connection between the two sources of power (UPS and BYPASS). Then turn the switch to
the BYPASS position and turn the UPS and the bypass circuit breaker ON so that power from
both sources is available at the bypass switch.
Verify the following voltages shown in Table 3 below.
CAUTION: DO NOT OPERATE THE SWITCH IF THE MEASURED VOLTAGES ARE
GREATER THAN SHOWN IN TABLE 3 ABOVE.
If you cannot obtain the indicated voltages, check your wire connections. For example, is L1
of the UPS input connected to the same phase as L1 of the bypass line? Also check the input
and output voltages of the UPS and / or the Bypass Transformer as shown in Table 4. Contact
ALPHA if the phasing is not correct or if you need further assistance.
Table 3 - BPS Voltages Phase Checks
Ground to Neutral
(GND to pin 5/7 of BPS )
< 5 V
Ground to L1
(GND to pin 1/3 of BPS )
110 - 125 V
Ground to L2
(GND to pin 9/11 of BPS ) 110 - 130 V if 240 V system
75 - 95 V if 208 V system
L1, UPS - BYPASS
(pin 2 to pin 4 of BPS)
< 20 V
< 100 V
N, UPS - BYPASS
(pin 6 to pin 8 of BPS)
< 20 V
< 20 V
L2, UPS - BYPASS
(pin 10 to pin 12 of BPS)
< 20 V
< 100 V
Voltage Check:
Measuring Points
Measured Voltages
Make-Before-
Break Bypass
Switch
Break-Before-
Make Bypass
Switch
Measuring Points
Phase Check:
Table 4 - UPS / BPT Voltage and Phase Checks
(All measurements are at no load)
CFR with 120 Volt input
input L1 to output L1
< 30 V
> 180 V
input L2 to output L1
> 180 V
< 30 V
CFR with 208 or 240 V input
input L1 to output L1
< 100 V
> 180 V
input L2 to output L1
> 180 V
< 100 V
Bypass Transformer
H1 to X1
< 100 V
> 200 V
H1 to X5
> 200 V
< 100 V
UPS or BPT
Measuring Points
Correct Phas-
ing
Out of Phase
Operation
Doc# 020-133-B0 Rev. 01 / 07
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