Carrier HFC-134A installation instructions Lug Capacity, A23-1587

NOTES FOR FIG. 44

GENERAL

1.0Variable frequency drive (VFD) shall be designed and manufactured in accordance with Carrier engineering requirements.

1.1All field-supplied conductors, devices and the field- installation wiring, termination of conductors and devices, must be in compliance with all applicable codes and job specifications.

1.2The routing of field-installed conduit and conductors and the location of field-installed devices, must not interfere with equipment access or the reading, adjusting or servicing of any component.

1.3Equipment installation and all starting and control devices, must comply with details in equipment submittal drawings and literature.

1.4Contacts and switches are shown in the position they would assume with the circuit de-energized and the chiller shutdown.

1.5

Do not use aluminum conductors. Contractor/installer assumes all liability resulting from the use of aluminum conductors within the VFD enclosure.

POWER WIRING TO VFD

2.0Provide a means of disconnecting branch feeder power to VFD. Provide short circuit protection and interrupt capacity for branch feeder in compliance with all applicable codes.

2.1If metal conduit is used for the power wires, the last 4 feet or greater should be flexible to avoid transmitting unit vibration into the power lines and to aid in serviceability.

2.2Line side power conductor rating must meet VFD nameplate voltage and chiller minimum circuit ampacity.

2.3Lug adapters may be required if installation conditions dictate that conductors be sized beyond the minimum ampacity required. Circuit breaker lugs will accommodate the quantity (#) and size cables (per phase) as shown in Table 12.

2.4Compressor motor and controls must be grounded by using equipment grounding lug provided inside unit mounted VFD enclosure.

CONTROL WIRING

3.0Field-supplied control conductors to be at least 18 AWG or larger.

3.1Ice build start/terminate device contacts, remote start/stop device contacts and spare safety device contacts, (devices not supplied by Carrier), must have 24 VAC rating. Max cur- rent is 60 mA, nominal current is 10 mA. Switches with gold plated bifurcated contacts are recommended.

3.2Remove jumper wire between TB1-19 and TB1-20 before connecting auxiliary safeties between these terminals.

3.3Each integrated contact output can control loads (VA) for evaporator pump, condenser pump, tower fan low, tower fan high, and alarm annunciator devices rated 5 amps at 115 VAC and up to 3 amps at 277 VAC.

Control wiring required for Carrier to start pumps and tower fan motors and establish flows must be provided to assure machine protection. If primary pump, tower fan and flow control is by other means, also provide a parallel means for control by Carrier. Failure to do so could result in machine freeze-up or over-pressure.

Do not use control transformers in the control center as the power source for external or field-supplied contactor coils, actuator motors or any other loads.

3.4Do not route control wiring carrying 30 V or less within a conduit or tray which has wires carrying 50 V or higher or along side wires carrying 50 V or higher.

3.5Spare 4-20 mA output signal is designed for controllers with a non-grounded 4-20 mA input signal and a maximum input impedance of 500 ohms.

3.6Flow devices to confirm evaporator or condenser pump flow are not required. However; if flow devices are used, wire as shown on drawing 23XRC1-1 (J3 lower). Remove jumper installed at these terminals and wire in a 4.3 K resistor in its place.

CCM

J3 (LOWER)

a23-1587

The flow device and resistor must be installed in parallel at these terminals such that the resistor provides a signal when the flow device is open.

Table 12 — Lug Capacity

VFD	STANDARD 65K AIC LUG CAPACITY		OPTIONAL 100K AIC LUG CAPACITY
MAX. INPUT	(PER PHASE)		(PER PHASE)
AMPS.	No. Conductors	Conductor Range	No. Conductors	Conductor Range
225A	3	3/0 — 500MCM	2	3/0 — 250MCM
338A	3	3/0 — 500MCM	2	400 — 500MCM
440A	3	3/0 — 500MCM	2	400 — 500MCM
520A	3	3/0 — 500MCM	3	3/0 — 400MCM
608A	3	3/0 — 500MCM	3	3/0 — 400MCM

NOTE: If larger lugs are required, they can be purchased from the manufacturer of the circuit breaker (Cutler-Hammer or Square D).

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