Electrical Installation Requirements; Pump Requirements; Variable Frequency Drive Requirements; Figure 7: Variable Frequency Drive Mounting - Roberts Gorden UltraVac NEMA 4 Installation Manual

3.4 Electrical Installation Requirements

DANGER
Electrical Shock Hazard
Disconnect electrical before servicing.
This appliance must be connected to a
properly grounded electrical source.
Replace cover before operating.
Failure to follow these instructions can result
in death or electrical shock.
3.4.1 The enclosure must be supplied from a local
fused isolator rated for a total amperage not
exceeding 25 A.
The method for calculating the current loading is as
follows:
CORAYVAC ® Burner
Multiply the current for the individual burners above
by the number of burners supplied from the
enclosure to give the total current required.
The full load amps for the optional outside air blower
(P/N 90707500) are:
The total added current load for each individual
relay must not exceed 3 A.
The total added current load for all 8 relays must
not exceed 25 A.

3.5 Pump Requirements

The pump is powered directly from the Variable
Frequency Drive (VFD). The VFD will be energized
via an output from the relay board switched through a
designated relay.

3.6 Variable Frequency Drive Requirements

The VFD must be powered separately from the con-
trol enclosure. The 230 V drive power supply must be
230 V, 50-60 Hz, 1 Ø. The 120V drive power supply
must be 120 V, 50-60 Hz, 1 Ø. The 460 drive power
supply must be 460 V, 50-60 Hz, 3 Ø. See Page 9,
Section 2.3 for additional details. The VFD on/off
switching is done by an output on the relay board.
0.3 A/burner
1.6 A
The 0-10 V signal from the ULTRAVAC™ controller
enclosure wired into VFD input relays 5 and 2 (see
Page 16, Figure 11 through Page 18, Figure 12) will
dictate the speed of the pump. The VFD output sup-
ply to the pump is 230 V 3 Ø 0-60 Hz for 115 V and
230 V models and is 460 V, 3 Ø, 0-60 Hz for 460 V
models. The frequency of the output supply signal to
the pump will be varied based on the 0-10 V signal
from the control
enclosure. See Page 11, Section 3.2 for additional
installation requirements.

FIGURE 7: Variable Frequency Drive Mounting

(Standard enclosures only, NEMA 4 enclosure
mounting varies by model)
14 .75"
(37.5 cm)
SECTION 3: I
NSTALLATION
10" (25.4 cm)
13