Application Guide

ManualsBrandsHoneywell ManualsHVAC SuppliesSmart VFD HVAC Variable Frequency Drive, 460V, 30 HP, NEMA 1, Drive Alone

63-7062 48

Starting is also coarse as the motor is generally switched directly on to the power supply causing harsh acceleration. By

interfacing a VFD to the existing control, smoother starting is achieved and stopping is more precise. These both to accuracy of

approximately 1.5 mm. This is a fully controlled stop, so it is a repeatable process. It is not easy to give a design for a control

interface as there are so many different possibilities, but the VFD application engineer should be conversant with the

capabilities of the VFD to ensure that the correct mode of operation is employed.

Benefits

— Smooth start/stop.

— Accurate positioning.

— Easy retrofit.

— More reliable.

— Reduced wear on brakes.

VFD Features Used

— Digital control.

— Multi-fixed speed control.

— Auto restart.

IMPORTANT

1. The deceleration phase generally is more arduous for the VFD as it has to absorb a large amount of energy from the

car.

2. Under normal circumstances the VFD is NOT capable of handling this energy without tripping. A regenerative braking

unit should be connected to dissipate this energy safely.

3. This is one of the most difficult applications as the performance has to be repeated many times throughout the

working day. As many as 200 starts per hour are not uncommon.

List of Abbreviations

AHU Air Heating Unit

AQ Air Quality

CAV Constant Air Volume

CC Chiller Controller

CHW Chilled Water

DDC Direct Digital Control

DP Differential Pressure Sensor

HVAC Heating, Ventilation, Air Conditioning

ID Induced Draught

M Motor

PS Pressure Sensor

P + I Proportional and Integral Control

T Temperature Sensor

TS Temperature Switch

TT Temperature Transmitter

VValve

VAV Variable Air Volume

PRE POWER UP CHECKS

Inspect internal condition of VFD for physical damage.

If the output (motor) cables from the VFD have been connected to the VFD terminals, disconnect them before powering

up for the first time.

NOTE It is very easy to confuse the input and output cabling resulting in one or more of the commercial electrical

supply phases to be connected to the VFD output. If this occurs when power is applied, it is likely to damage to

the VFD.

Make a general inspection of the internal condition of the VFD and its cubicle. Check for debris that can cause short

circuits. Be aware that debris can fall down through the heat sink and become lodged in internal cooling fan.