Sullair SUPERVISOR CONTROLLER Instruction Manual

Section 3
SEQUENCING WITH VARIABLE
SPEED DRIVE COMPRESSORS
15
3. SEQUENCING WITH VARIABLE SPEED DRIVE COMPRESSORS
3.1 VARIABLE SPEED DRIVE APPLICATIONS
A multiple-compressor system can be designed using a variable-speed-drive (VSD)
compressor combined with other VSD compressors or fixed speed compressors. The
most efficient use of a VSD machine in sequencing is to set it up to always be the trim
machine and always running. This is accomplished using existing Sullair sequencing
logic as explained in the following sections.
3.2 SETUP FOR FIXED SPEED MACHINES AND A VSD COMPRESSOR
The fixed-speed machines in a mixed sequence system must always be set up for
load/unload operation. If controlled with Supervisor II Deluxe controllers, the pressure
regulator/s must be made to have no effect by setting the system to operate below the
effective range of the regulators. If controlled by the Supervisor Controller or WS
Controllers, the controls may be programmed for Load/No load operation. In this
configuration, the Full Load valve is energized any time the machine is running, thus
defeating modulation. Alternately, the Full Load solenoid valve may be rewired to the
Load output with any of the controllers (Supervisor Controller, Supervisor II Deluxe, or
WS) to achieve the same results. In all cases, care must be taken to not overload the
compressors by limiting operation to pressures within the capability of the drive motor.
See Table 3.1 for suggested settings of compressors in a mixed sequence configuration.
These settings are typical for a target system pressure of 99 psi at discharge of
compressors.
Table 3.1 Mixed System Settings (Target Pressure: 99 psi)
Parameter VSD Compressor
Settings
Fixed-Speed Compressor(s)
Settings
Unload Setpoint 104 102
Load Delta 6 6
VSD Setpoint 99
Com # COM #1, 2 (, 3, 4, etc.)
Lowest Pressure 90
Since this machine is to always be the trim machine, no Full Load action is needed. The
Max Speed input signal should be disabled unless more than one VSD machine is in the
same sequence.
In this configuration, only the fixed-speed compressors are sequenced and the VSD
machine is run with its sequencing disabled. The Sequence hours mode can then be
used to automatically rotate the fixed-speed machines, or the fixed-speed machines may
be sequenced based on Com #.
Depending on the application and system demands, the VSD compressor can either be
run continuously or in the AUTO mode. This will allow the unload time to be minimize to
as low as an immediate stop on unload.
This arrangement sets the VSD machine to always restart at a higher pressure than the
fixed-speed machines thus forcing it to always operate as the trim machine. By adjusting

Sullair SUPERVISOR CONTROLLER Specifications

General

Brand	Sullair
Model	SUPERVISOR CONTROLLER
Category	Controller
Language	English