Emerson Copeland Scroll ZPV066, Бюллетень

Страница: 5 / 23

© 2017 Emerson Climate Technologies, Inc.
5
AE4-1414
APPLICATION CONSIDERATIONS
Compressor Temperature Protection
A discharge line thermistor must be used to protect the
compressor. The drive will shut down the compressor
when the thermistor temperature exceeds 275°F
(135°C). Please see the section
Troubleshooting
Scroll Temperature Trip for more information on the
discharge line thermistor. Refer to Table 1 for more
information.
Variable Speed Drive Options
Third Party Drive
The customer may use a third party drive. A third
party control system must include: a discharge line
thermistor that will signal the drive to shut down if the
temperature exceeds 275°F (135°C), a soft start and
stopping routine, an oil boost cycle similar to the
Emerson EVC oil boost, and include the operating
envelope. A third party drive must include short cycle
protection similar to the Emerson EVC short cycle
protection. Refer to
Table 2 for compressor motor
specifications and Table 5 for speed adjustment
requirements.
Emerson EVC Drive Features
It's recommended that the Emerson variable speed
drive (VSD) be used with the variable speed
compressor. The Emerson VSD has custom built in
features that may improve the longevity of the
compressor and efficiency of the system. Refer to
the Emerson EVC Drive user guide for more
information.
Oil Boost
The Emerson EVC drive includes an oil boost cycle
when the compressor operates at less than 1800
RPM. The oil boost cycle starts once the
compressor operates for two hours at less than
1800 RPM. During the oil boost cycle, the drive
forces the compressor to run for five minutes at
3600 RPM. After operating for five minutes at 3600
RPM, the drive allows the compressor to operate
at less than 1800 RPM. The operating envelope
shows the operating conditions of the oil boost
cycle.
Motor Protection
The Emerson EVC drive includes motor protection
features for the compressor. The drive sets the
maximum current limit, low voltage fold back which
allows the compressor to ride through low voltage
situations, which helps keep the compressor
running to avoid nuisance trips. The drive also
includes lost rotor avoidance and locked rotor
detection. The lost rotor avoidance uses a custom
algorithm to evade a speed error by reducing the
speed by 200 RPM to 're-catch' the rotor.
Missing Phase Protection
The Emerson EVC drive includes compressor
missing phase protection. The drive checks for a
missing phase connection.
Short Cycle Protection
The Emerson EVC drive includes short cycling
protection which checks the duration of the runtime
and quantity of short cycles. The amount of
runtime and the maximum allowable short cycles in
24 hours is adjustable. The default maximum short
cycles in 24 hours is four. The default short cycle
time is five minutes.
Resonance Avoidance Feature
The Emerson EVC drive includes a resonance
avoidance feature which has the ability to skip a
single frequency or a range of frequencies.
Discharge Temperature Protection
The thermistor will signal the drive to shut down if
the temperature exceeds 275°F (135°C).
Emerson EVC Operating Envelope
When using the Emerson EVC drive, the
compressor is designed to operate within the
requirements of the operating envelope.
Emerson EVC Starting and Stopping Routine
The drive controls the starting and stopping routine
of the variable speed scroll. This routine allows soft
starting and controlled stopping, an advantage
over traditional on-off control of fixed capacity
units. Please refer to the Emerson EVC drive user
guide for an exact explanation of the starting and
stopping process.
The variable speed scroll compressor incorporates
a fluid brake design to help mitigate reverse
rotation during shutdown. A momentary reverse
rotation sound may be heard. Refer to
Table 5 for
more information.
Other Features
Refer to the Emerson EVC drive user guide for
more features and functions of the drive.