Emerson Copeland YHV029RG Application Manuallines page 14

Please consider the following about the operating envelopes:
Bef ore compressor start with the matched pair of YHV*RG and YHV*RT and ED3/EV3 drive, the
pressure difference in the system must be below 10 bar. If the pressure difference is reduced by
opening the expansion valve, care must be taken to avoid liquid floodback to the compressor
also see section 3.16 "Suction line accumulator" and the oil dilution chart in section 3.15
"Compressor oil return, oil balancing, floodback and oil dilution tests".
Bef ore each compressor start-up, the minimum off time, which is def ined as the time elapsed
since the previous shutdown, must be at least 1 minute.
An oil return test for the system must be performed. If required, the system design must be
improved to ensure suf ficient oil return f rom the system to the compressor
5.15 "Oil level".
The system should be able to bring the compressor to a point inside the envelope as f ast as
possible start-up, and to keep the compressor running there. Running outside the envelope is not
f or 30 seconds or longer until the system is in stable operation see Figure 9 "Ramp up".
Ramp up
3000
720
0
System Controller
ED3
Figure 9: Ramp up and controlled shutdown
Running/oscillating the compressor in and out of the envelope borders is not allowed and should
be avoided.
Running the compressor below the envelope at low condensing temperat ures is possible for no
longer than 30 minutes but users must be aware that unloading noise from the compressor can
occur. In that area, the speed limits according to the evaporating temperatures in the envelope
should be respected.
The qualif ied application envelopes will change with the compressor speed. At all operating
conditions the minimum and maximum speed limits according to Figures 7 & 8 must be
respected. With changing operating conditions, the speed limits have to be determined by linear
interpolation between the limits given in Figures 7 & 8. See also speed limit animations in Select
sof tware at www.climate.emerson.com/en-gb.
Fast speed changes can cause instable control, eg, on the superheat control. Per Emerson
experience speed changes should be in the range of 10 to 60 rpm/s depending on the system
reaction.
The system controller should adequately take care of controlling the envelope.
To stop the compressor, reduce the speed to 3000 rpm then stop the compressor see Figure 9
"Controlled shutdown".
Bef ore f irst start, each drive has to be set with the compressor model. This provides a speed-
dependent maximum torque protection related to the compressor model. The maximum torque
requirement will follow, with some margin, the maximum condensing temperature line f or each
speed. If the torque exceeds the maximum torque allowed for a specific speed, the drive will reduce
the speed of the compressor in an attempt to keep the operating condition within the operating
envelope. If reducing the speed of the compressor does not bring the condensing temperature back
down within the envelope, the drive will go to the next level of protection and shut down the
compressor.
This drive f eature aims at protecting the drive and the compressor. It cannot be used in the system
as an operating envelope limitation.
AGL_HP_VS_YHV_RG_RT_EN_Rev00
Speed control
Hold
Min 30s
Controlled
Speed control
shutdown
3000
0
also see section
9