Danfoss TG230 Series, Installation Manual

Page: 14 / 108

Page 14 of 108 M-AP-001-EN Rev. N
M-AP-001-EN Rev. N
* Danfoss Turbocor’s commitment to excellence ensures continuous product improvements.
* Subject to change without notice.
Introduction
Acronym / Term Definition
Shaft Orbit The path travelled by the compressor shaft relative to the bearing magnetic centers
Shrouded Impeller An impeller with boxed in, or “shrouded,” impeller blades, as opposed to an open impeller.
SIE Semi-Integrated Electronics version of the compressor.
Single-Stage
Centrifugal
compressor
Type of centrifugal compressor having one impeller.
Snubbers
Capacitors responsible for eliminating electrical noise/harmonics from the DC Bus before it
reaches the IGBT
Soft-Start Board /
Soft-
Starter
The Soft-Start Board limits in-rush current by progressively increasing the conduction
angle of the SCRs. This technique is used at compressor startup while the DC capacitors are
charging up. The Soft-Start Board takes as input a 3-phase voltage source at 50/60Hz from
the input terminal and a DC voltage signal from the SCR output. In turn, it outputs pulses
to the SCR and provides power to the High-Voltage (HV) DC-DC Converter. All voltages
from the Soft-Start Board are with respect to the positive DC bus and not the compressor
ground.
SST Saturated Suction Temperature
Surge
The condition at which the compressor cannot sustain the discharge pressure, allowing
refrigerant to temporarily and rapidly re-enter the compressor fluid path, creating a
cavitating effect. This is an undesirable situation that should be avoided.
Thrust Bearing
A bearing that absorbs the axial forces produced in a centrifugal compressor by the
refrigerant pressure differential across the impeller.
Ton The basic unit for measuring the rate of heat transfer (12,000 BTU/H; 3.516 kw/H)
Touchdown
Bearings
Carbon races or ball bearing for the purpose of preventing mechanical interference
between the shaft and the magnetic bearings should they lose power or fail.
TT Twin Turbine
Two-Stage
Centrifugal
compressor
Type of centrifugal compressor having two impellers. The first-stage impeller raises the
pressure of the refrigerant vapor approximately halfway from the cooler pressure to the
condenser pressure, and the second-stage impeller raises the pressure the rest of the
way. With a two-stage compressor, an interstage economizer may be used to improve the
refrigeration cycle efficiency
TXV
Thermal Expansion Valve. A pressure-dependent refrigerant metering device that operates
independently and is controlled by temperature.
UL Underwriters Laboratories (www.ul.com)
Up-Trip Voltage When the DC- bus reaches the up-trip voltage, the SCRs will be gated open continuously
VAC Volts Alternating Current
Vaned Diffuser
An assembly of plates with curved vanes that serve to slow, compress, and reduce
refrigerant rotation as it enters the second-stage impeller
Vaneless Diffuser Similar to a Vaned Diffuser, except that it does not possess any de-swirl vanes
VDC Volts Direct Current
VFD Variable Frequency Drive