Frick Vyper 254, Установка, эксплуатация и обслуживание, Страница: 11 / 68

VYPER ™ VARIABLE SPEED DRIVE
INSTALLATION
100-200 IOM (FEB 09)
Page 11
Recommended Analog signal wire
0.750 mm2 (18AWG) twisted pair, 100% shield with drain.
If the wires are short and contained within a cabinet which
has no sensitive circuits, the use of shielded wire may not
be necessary, but is always recommended.
Recommended Digital signal wire
Unshielded Per US NEC or applicable electrical code.
Shielded 0.750 mm2 (18AWG), 3 conductor, shielded.
TRANSFORMERS
In most installations the transformer that supplies the refrig-
eration equipment is the same transformer that powers most
of the other loads in the same building. These transformers
are generally very large relative to the refrigeration load.
However is some case there will be an individual transformer,
sized and dedicated to the refrigeration system alone. For
example, when a 460 VAC VSD is used and the existing
power is 208V, a 208 V to 460V step-up transformer should
be installed.
Such transformers must be specially sized whenever a
Vyper
™
is involved. Failure to properly size the transformer
may result in unreliable operation. NOTE: Contact the fac-
tory or power provider for transformer sizing.
NOTE: Transformer must be K4 rated.
When installing a Vyper
™
on an existing transformer, the
total KVA requirement of the VSD controlled system and all
branch circuits must be considered. The transformer sup-
plying the Vyper
™
shall be sized such that the transformer
voltage does not sag more than 5% when subjected to load
excursions. The steady-state operating voltage should be
within the range of 414 to 508 VAC, 3 phase 60 Hz, or 342-
423 VAC, 3 phase, 50 Hz.
KVA Impedance Weight (lb)
175 5%-6% 1100
220 5%-6% 1470
275 5%-6% 1750
330 5%-6% 1990
440 5.5% - 6.5% 2700
550 5.5% - 6.5% 3100
660 5.5% - 6.5% 3600
750 6% - 7% 4600
880 6% - 7% 5300
990 6% - 7% 5800
1250 6.5% - 7.5% 6200
1500 6.5% - 7.5% 6800
1750 6.5% - 7.5% 7500
2000 6.5% - 7.5% 8200
Johnson Controls offers a line of Recommended Vyper
VSD Transformers. These transformers have the following
features:
• Steel core for low flux density operation.
• Standard K-4 rating. K-13, K-20, K-30 is available as an
option.
• UL / CSA certified.
• 600 Volt class
•
Primary Voltage: 208V, 230V, 460V, 575V
• Conductors, 40°C ambient
•
Sinusoidal loading not to exceed K-4
• Secondary Voltage: 460
• NEMA 2 housing
• 60 Hz, 150°C temperature rise, 220°C insulation
• Taps: 1 plus, 1 minus@5%
POWER FACTOR CAPACITORS
Power factor correction capacitors are not required since the
Vyper
™
has a 0.95 minimum power factor at all operational
loads and conditions. Capacitors can be located at one or
several places on a distribution system. Solid-state motor
controllers may not run, or have difficulty starting in that
scenario. The degree of malfunction depends on the size of
the capacitors, the distance away for the solid-state controls,
and the size of the building supply transformer.
With a VSD there is no way to know in advance whether the
capacitors will cause interference. When a VSD is started and
there are problems cause by power factor capacitors, it will be
necessary to remove those capacitors. In some installations,
capacitors are switched on line as power factor drops.
The switching transients created by connecting and discon-
necting power factor capacitors may cause the Vyper
™
to drop
off-line. High voltage power factor capacitors may be located
on the primary side of the transformer supplying power to
the Vyper
™
without causing any malfunction to equipment
on the secondary side.
SOFT-START SEQUENCE
At start-up, both the motor and slide valve begin to load to
a preset value.
NOTE: There is a 30 second delay at initial start-up to
charge the capacitors of the Vyper ™ . This delay does not
occur in Standby mode, only on initial start-up.
The Frick slide valve will load to the Variable Speed Minimum
Slide Valve Position setpoint, and the Vyper accelerates to the
speed corresponding to the Minimum Drive Output setpoint.
From this point the slide valve position and motor speed are
controlled by the Capacity Control setpoints.
During start-up, the VSD varies the voltage and frequency
to maintain the same proportion that exists between the two
at design conditions. The required inrush current to start the
motor never exceeds the FLA rating of the given motor and is
typically only 10-20% of FLA. Mechanical forces on the motor
windings and motor heating are 20% to 50% lower than with
a mechanical starter. This results in less mechanical shock
to the system and longer motor life.
INTERFACING ElECTRICAl EQUIPMENT
There are many low voltage DC signals in the Vyper ™ which
may be picked up from other electrical devices or wiring in the
vicinity of the electronic controls. It is essential that non-VSD
wiring is not routed through the Vyper ™ cabinet. It is equally
important that no external equipment is tied to the Vyper
™
control wiring in any way. A control system should never be
wired to the Vyper
™
circuitry. Never use 120V supply to feed
the VSD control wiring. The Vyper ™ has it’s own internal
power supply. Using an external supply may damage the
Vyper
™
and may also cause hazardous working conditions
for service and operating personnel.