Electrical Notes - York YCAS Installation Operation & Maintenance

Air-cooled liquid chillers

Table of Contents

Technical Data

NOTES

MRA is Maximum Running Amps, the maximum continuous current at any operating point in the rating range. Also referred to as MCA, or

Minimum Circuit Ampacity to be provided by the installer. If a factory mounted Control Transformer is provided, add 3 amps to the system

#1 MCA values in the YCAS Tables.

The recommended disconnect switch is based on a minimum of 115% of the summation rated load amps of all the loads included in the

circuit, per N.E.C. 440 - 12A1.

Minimum recommended fuse size is based on 150% of the largest motor RLA plus 100% of the remaining RLAs (U.L. Standard 1995,

Section 36.1). Minimum fuse rating = (1.5 x largest compressor RLA) + other compressor RLAs + (# fans x each fan motor FLA).

Maximum dual element fuse size is based on 225% maximum plus 100% of the rated load amps for all other loads included in the circuit,

per N.E.C. 440-22. Maximum fuse rating = (2.25 x largest compressor RLA) + other compressor RLAs + (# fans x each fan motor FLA).

Minimum recommended circuit breaker is 150% maximum plus 100% of rated load amps included in the circuit, per circuit per U.L. 1995

Fig. 36.2. Minimum circuit breaker rating = (1.5 x largest compressor RLA) + other compressor RLAs + (# fans x each fan motor FLA).

Maximum circuit breaker is based on 225% maximum plus 100% of the rated load amps for all loads included in the circuit, per circuit, per

U.L. 1995 Fig. 36.2. Maximum circuit breaker rating = (2.25 x largest compressor RLA) + other com pres sor RLAs + ( # fans x each fan

motor FLA).

The Incoming Wire Range is the minimum and maximum wire size that can be accommodated by unit wiring lugs. The (1), (2), or (3)

indicate the number of termination points or lugs which are available per phase. Actual wire size and number of wires per phase must be

determined based on ampacity and job requirements using N.E.C. wire sizing information. The above recommendations are based on the

National Electrical Code and using copper conductors only. Field wiring must also comply with local codes.

A ground lug is provided for each compressor system to accommodate Þ eld grounding conductor per N.E.C. Article 250-54. A control circuit

grounding lug is also supplied. Incoming ground wire range is #6 - 350 MCM.

The Þ eld supplied disconnect is a "Disconnecting Means" as deÞ ned in N.E.C. 100.B, and is intended for isolating the unit from the available

power supply to perform maintenance and troubleshooting. This disconnect is not intended to be a Load Break Device.

10. Two-Compressor machines with single-point power connection, and equipped with Star (Wye)-Delta Compressor motor start must also

include factory-provided individual system circuit breakers in each motor control center. All 3 & 4 Compressor machines equipped with

Star-Delta com pres sor motor start must also include factory-provided individual system circuit breakers in each motor control center.

11.

Consult factory for Electrical Data on units equipped with "High Static Fan" Option. 50 Hz Fans are 3.5 kW each.

12.

FLA for each "Low Noise Fan" motor is 4.1A.

13.

Group Rated Breaker must be HACR type for cU.L. machines.