Table of Contents
Advertisement
Legend and Notes for Table 8
LEGEND:
BRKR
--- Circuit breaker
CO
--- Convenient outlet
FLA
--- Full Load Amps
LRA
--- Locked Rotor Amps
MCA
--- Minimum Circuit Amps
Protection
NEC
--- National Electrical Code
PWRD CO
--- Powered convenient outlet
RLA
--- Rated Load Amps
UNPWR CO
--- Unpowered convenient outlet
NOTES:
1. In compliance with NEC requirements for multimotor and
combination load equipment (refer to NEC Articles 430 and
440), the overcurrent protective device for the unit shall be
fuse or HACR breaker. Canadian units may be fuse or circuit
breaker.
2. The MCA values are calculated in accordance with The NEC.
Article 440.
3. Motor RLA and LRA values are established in accordance
with Underwriters' Laboratories (UL). Standard 1995.
4. The 575--- v units are UL, Canada--- listed only.
5. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply
voltage is greater than 2%. Use the following formula to de-
termine the percentage of voltage imbalance.
Step 8 — Wind Baffles for Low Ambient Control
38AUQB and 38AUQE units includes the factory installed
32LT Motormaster Low Ambient Control.
Units with 32LT Motormaster control require the addition
of wind baffles to ensure full range low ambient
operation. Material data and dimensions for wind baffles
are included in the Appendix C section, Low Ambient
Control, starting on page 47. Fabricate the wind baffles
and mount per instructions.
Example: Supply voltage is 230-3-60
max voltage deviation from average voltage
% Voltage Imbalance
= 100 x
AB = 224 v
BC = 231 v
AC = 226 v
(224 + 231 + 226)
Average Voltage =
3
=
227
Determine maximum deviation from average voltage.
(AB) 227 – 224 = 3 v
(BC) 231 – 227 = 4 v
(AC) 227 – 226 = 1 v
Maximum deviation is 4 v.
Determine percent of voltage imbalance.
% Voltage Imbalance
= 100 x
= 1.76%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is more than
2%, contact your local electric utility company immediately.
17
average voltage
681
=
3
4
227
Advertisement
Table of Contents
