Frick XJS 95M User Manual

070-450 IOM (NOV 13)
Page 19
XJF ROTARY SCREW COMPRESSOR
INSTALLATION
ELECTRICAL INSTALLATION
CAPACITY SLIDE VALVE TRANSMITTER
The slide valve transmitter (Figure 9) measures the position
of the slide valve (SV) and sends a 4 to 20mA signal to your
control system. See Figure 10. The controller will adjust the
position of the SV according to the motor load set point.
The correct position is important to properly load the
compressor and motor. It is important not to overload the
compressor and motor. Observe the maximum power input
and ensure design limitations are not exceeded. Connect to
+/- and signal as shown in the wiring diagram, Figure 10.
Refer to Frick compressor panel instructions for calibration
procedure 090.040-O.
Figure 9 - Slide Valve Transmitter
Figure 10 - Wiring Diagram for Slide Valve Transmitter
COMPRESSOR HYDRAULIC SYSTEM
The hydraulic system of the XJF compressor utilizes oil pres-
sure from internally drilled passages in the compressor casing
to selectively load and unload the compressor by applying this
pressure to the actuating hydraulic piston of the movable slide
valve (MSV). It also uses oil pressure to actuate a hydraulic
piston that moves the movable slide stop, Volumizer II. This
allows adjustment of the compressor volume ratio, (Vi) while
the compressor is running.
CAPACITY CONTROL
COMPRESSOR LOADING: The compressor loads when MSV
solenoid coil YY2 is energized and oil ows from the solenoid
valve through the needle valve (HV2) to compressor port 2,
where it enters the load side of the slide valve piston. This
equalizes the force on the slide valve piston and discharge
pressure on the slide valve area loads the compressor. See
Figure 11.
Figure 11 - Hydraulic Schematic
COMPRESSOR UNLOADING: The compressor unloads when
MSV solenoid YY1 is energized and oil is allowed to ow
from compressor port 2 thru the needle valve to the MSV
solenoid. This allows discharge pressure on the slide valve
piston to unload the slide valve as the piston moves outward.
ADJUSTMENT (Capacity Control): A needle valve (HV2)
is provided to adjust slide valve travel time, preventing
excessive slide valve “hunting”. HV2 should be adjusted to
restrict oil ow to the compressor port so that slide valve
travel time from full load to full unload, or vice versa, is a
minimum of 30 seconds.
NOTICE
A change in operating conditions, such as winter-to-
summer operation, may require readjustment of slide
valve travel time.
VOLUMIZER II Vi CONTROL
The XJF compressor is equipped with a special internal
control that automatically adjusts the compressor volume
ratio to the most efcient of three available steps, (2.2, 3.5,
or 5.0 volume ratio). This gives the compressor the ability
to operate at varying operating conditions while minimizing
power consumption by avoiding over or undercompression.
Solenoid valves 3 and 4 (See Figures 12 - 14 and location
on P & I diagram represented by YY3 and YY4) control the
Volumizer II volume ratio control. Oil is internally ported to
apply hydraulic pressure to two stepping pistons in order
to move the moveable slide stop to the optimum position.
The following chart shows the logic of solenoid operation
to adjust the volume ratio.
Vi SOLENOID 3 / YY3 SOLENOID 4 / YY4
2.2 Energized Energized
3.5 Deenergized Energized
5.0 Deenergized Deenergized
Proper operation of the Volumizer II control can be checked
as follows.
1. Conrm that the slide valve travel number in Factory Setup
is set at 190 degrees. If necessary, adjust the setting to 190
degrees before proceeding further.
2. Set the compressor Vi to 2.2, then record the voltage that
is shown on the Slide Valve calibration screen for the cur-
rent Slide Valve and 0% Slide Valve positions. The difference
between these voltages must be in the 1.35 - 1.65 Vdc range.

Frick XJS 95M Specifications

General

Brand	Frick
Model	XJS 95M
Category	Air Compressor
Language	English