York YR manual Electrical Considerations, Ampacity on Line Side of Starter, Motor Electrical Data

FORM 160.81-EG1

Application Data (continued)

In addition, the ASHRAE Standard 15 requires a refriger- ant vapor detector to be employed for all refrigerants. It is to be located in area where refrigerant from a leak would be likely to concentrate. An alarm is to be activated and the mechanical ventilation started at a value no greater than the TLV (Threshold Limit Value) of the refrigerant.

ELECTRICAL CONSIDERATIONS

Motor Voltage – Low voltage motors (200 - 600 volts) are furnished with six leads. Motor circuit conductor size must be in accordance with the National Electrical Code (NEC), or other applicable codes, for the motor full- load amperes (FLA). Flexible conduit should be used for the last several feet to the chiller in order to provide vibration isolation. Table 2 lists the allowable variation in voltage supplied to the chiller motor. The unit name- plate is stamped with the specific motor voltage and fre- quency for the appropriate motor.

TABLE 2 – MOTOR VOLTAGE VARIATIONS

FREQ.	RATED	NAMEPLATE	OPERATING VOLTAGE
	VOLTAGE	VOLTAGE	MIN.	MAX.
	200	200/208	180	220
	230	220/240	208	254
60 HZ	380	380	342	415
	460	440/460/480	414	508
	575	575/600	520	635
50 HZ	380	380/400	342	423
	415	415	374	440

Starters – The chiller is available with a factory-mounted and wired YORK Solid State Starter for 200 - 600 volt applications. Other types of remote mounted starters are available. These electro-mechanical starters must be furnished in accordance with YORK Standard R- 1131. Specification. This will ensure that starter com- ponents, controls, circuits, and terminal markings will be suitable for required overall system performance.

Controls – A 115 volt, single phase, 60 or 50 Hertz (4.5 kVa) power supply must be furnished to the chiller from a separate, fused disconnect or from a control transformer included as an option with electro-mechani- cal starters. No field control wiring is required, when the YORK SSS is supplied.

Copper Conductors – Only copper conductors should be connected to compressor motors and starters. Alu- minum conductors have proven to be unsatisfactory when connected to copper lugs. Aluminum oxide and the difference in thermal conductivity between copper and aluminum cannot guarantee the required tight con- nection over a long period of time.

Power Factor Correction Capacitors – Capacitors can be applied to a chiller for the purpose of power factor correction. For remote-MountedElectro-Mechanical Starters, the capacitors should be located on the load side of the starter. For YORK SSS, the capacitors must be located on the line side of the starter. The capacitors must be sized and installed to meet the National Elec- trical Code (NEC) and be verified by YORK.

Ampacity on Load Side of Starter – Electrical power wire size to the chiller is based on the minimum unit ampacity. For YORK SSS, this wiring is done at the factory. For remote starters, the National Electrical Code defines the calculation of ampacity, as summarized be- low. More specific information on actual amperage rat- ings will be supplied with the submittal drawings.

•Six-lead type of starting (Star-Delta)

Minimum circuit ampacity per conductor (1 of 6): Ampacity = .721 x compressor motor amps.

•Three-lead type of starting (Across-the-Line, Autotransformer and Primary Reactor)

Minimum circuit ampacity per conductor (1 of 3): Ampacity = 1.25 x compressor motor amps.

Ampacity on Line Side of Starter –

The only additional load on the circuit for the chiller would be the control transformer, unless it is supplied by a separate source.

Min. Circuit Ampacity =	125% of compr.	+	FLA of all other
	motor amps		loads on the circuit

Branch Circuit Overcurrent Protection – The branch circuit overcurrent protection device(s) should be a time- delay type, with a minimum rating equal to the next stan- dard fuse/breaker rating above the calculated value. It is calculated taking into account the compressor motor amps and may also include control transformer. Refer to submittal drawings for the specific calculations for each application.

MOTOR ELECTRICAL DATA

The full-load amperes (FLA) listed in Tables 3 and 4 are maximum values and correspond to the maximum motor kW listed. When the Input power (kW) is less than maximum motor kW, the FLA should be reduced using the following equation:

22 YORK INTERNATIONAL