JOHNSON CONTROLS
7
FORM 160.00-O10
ISSUE DATE: 8/24/2020
1
This instruction is to be used in conjunction with the
Operation Instructions for YORK Centrifugal chillers
furnished with an optional OptiSpeed™ Compressor
Drive (OSCD) see associated literature.
OPTISPEED COMPRESSOR DRIVE
OVERVIEW
OptiSpeed Compressor Drive 1100/1300 HP
The YORK® OptiSpeed Compressor Drive (OSCD) is
specifically designed for the application of controlling
an induction motor used on the YORK Model YK Cen-
trifugal Liquid Chiller. This type of design allows the
chiller to be design as a complete system, and take full
advantage of the strengths of each major component
within the system.
This new OSCD design builds on the successes of pre-
vious designs by being chiller mounted, provide for
high levels of energy savings, improved integration
with the chiller control center, liquid cooled, shell and
tube heat exchanger, use of fast switching power mod-
ules, high reliability, and greater ease of service.
New features include:
• Circuit breaker with ground fault detection.
• Lower current levels are now require for ground
fault detection from the drive logic board.
• Direct liquid cooling of power modules.
• A more accessible cooling system.
• Variable voltage input.
• Variable voltage output to support a wider voltage
range of motors.
• The harmonic filter is standard on all models.
• Modular lighter weight power units that can be re-
paired in the field without complete replacement.
• Ease of maintenance and setup.
OPTISPEED COMPRESSOR DRIVE
FEATURES
The new drive design is currently available in an
1100/1300 HP model. There are 3 power units used in
this model. Each power unit contains all of the power
devices required for one phase of input and output. In
other words, the rectifier and inverter are integrated
into one power unit.
This design has 2 methods of detecting a ground fault.
The circuit breaker has the ability to detect a ground
fault, as well as the drive logic board using data from
the input current sensors
Direct liquid cooling is a much more efficient way
of removing heat from the OSCD. This method also
reduces the cooling load on the internal cooling coil.
In the past, YORK developed direct liquid cooling for
the inverter power modules, but today YORK is direct
liquid cooling the rectifier, inverter, input inductor,
and the output inductor.
The cooling system for the OSCD is greatly modified
to improve serviceability of the power electronics. Re-
pair of the power electronics no longer requires access
to the back of the drive except to drain the cooling sys-
tem. Also, the use of a shell and tube heat exchanger is
standard on all models.
The OSCD can now be configured for many different
input voltage levels. Lower input voltages may de-rate
the input power rating of the OSCD, but the OSCD
will produce the same output voltage and will use the
same motor.
The harmonic filter is no longer an option, and the
function of the harmonic filter is included in a new rec-
tifier module. This type of arrangement for the recti-
fier no longer requires a separate power unit for the
harmonic filter. Also this rectifier is part of the power
unit for the inverter, thus reducing the number of parts
required and increasing reliability.
The new OSCD control system allows for different
motor voltages to be used. In a new production chiller
the OSCD will support a 575 VAC motor. In retrofit
applications the drive will support a 575 VAC motor
or a 460 VAC, motor regardless on the input voltage
provided to the OSCD.
SECTION 1 - GENERAL INFORMATION
