Connections; Vacuum Limiting Valve; Pump Thermal Supervision - Nederman RBU Serie Manual De Usuario

9 Base.
EN
10 a) Thermal fuse. b) PT1000 temperature sensor
(on models intended for use with a variable fre-
quency drive).
11 3-lobe roots-pump.
12 Inlet silencer with safety grating.
13 Universal valve. This is a combined vacuum limit-
ing valve, backflush valve, and overpressure valve.
14 Vacuum limiting valve disc.
15 Maximum work vacuum regulator.
16 Safety vacuum regulator. The regulator must not
be adjusted.
17 Inlet safety grating.
18 Overpressure valve.
4.1 Connections
The motor is connected electrically with the enclosure
roof removed. See the start- and control unit's manu-
al for electrical connections. Connections may vary de-
pending on the options. Connecting material such as
cables is not included with the unit. Different dust col-
lectors are available; see the manual of the dust col-
lector for details.
Start- and control units from Nederman have termin-
als for easy connection of all control cables. If other
equipment is used, this equipment must be similarly
equipped and connected for the guarantee of the RBU
unit to be valid. Most failures are result from faults
in the electrical equipment or connections. The mo-
tor overload relay must be of the 'heavy start type' as
some units are heavy to start. Otherwise, the motor
overload may trip because of the high current and the
long time spent in the Y-mode.
Figure 3 contains a schematic diagram of the normal
connections. These are as follows:
1 Exhaust duct in steel spiro for indoor installation.
2 Optional: 'Jet cap' for outdoor installation.
3 Vacuum pipe in non-spiro steel from the dust col-
lector.
4 3-phase supply.
5 Start- and control unit. Normally with a frequency
converter or Y/D-starting.
6 Optional: Pilot signal cable for installations with
automatic start/stop.
7 6 mm (1/4") tube airline to the universal valve. The
tube is supplied with the unit.
8 T-joint for the airline to the dust collector. See the
dust collector manual for more information.
9 Dirt and water separator for compressed air. The
separator is supplied with the unit.
10 Dust collector for 1–2 units. The dust collector is
ordered separately.
11 Cable to filter cleaning unit. See the dust collector
manual for more information.
16
RBU
12 Two lead cable to thermal fuse, see also
ure 5. The cable can be combined with the cable to
solenoid V1, item 13, into a single four lead cable.
13 Two lead cable to solenoid V1 on the universal
valve, see also Figure 4. This cable can be com-
bined with the cable to the thermal fuse, item 12,
into a single four lead cable.
14 Six lead cable for connecting the PT1000 sensors
to temperature supervision device (e.g. variable
frequency drive). Only on models intended for use
with a variable frequency drive.
15 Optional maintenance switch. For models inten-
ded for use with a variable frequency drive, an
EMC-compliant switch must be used. This is re-
quired in most countries.
16 Vacuum meter. The meter is linked to the vacuum
unit nipple by a 6 mm (1/4") tubing. The meter is
supplied with the unit.
17 Motor cooling air outlet without any connections.
The inlet must always be kept free to prevent
overheating.
18 Ventilation opening with a noise trap without any
connections. The opening must always be kept
free to prevent overheating.
19 Vacuum unit.
4.2 Vacuum limiting valve
See wiring diagram for the start- and control unit for
connection of the 24 VDC solenoid valve V1.
4.3 Pump thermal supervision
Figure 5 shows the circuit diagram for the overheating
cut-out on the pump used for Y/D started models. The
circuit trips and stops the unit when the temperature
reaches 140 °C (284 °F).
Figure 5 also shows the connection diagram for the
PT1000 temperature sensors used in the models in-
tended for use with a variable frequency drive. The
pump temperature must be monitored and the unit
stopped if the temperature reaches 140°C.
The circuitry in the start- and control unit must
on no account allow the unit to re-start directly
when the thermal fuse is replaced or after the
pump temperature sensor has indicated a tem-
perature of 140°C or more. Instead, a manual
reset of a circuit in the start- and control unit
must be required. Voltage must not exceed 24
V.
Thermal tripping is to be indicated by a lamp or LED.
The manufacturer of the motor start- and control unit
is responsible for supplying a reliable circuit for this
purpose. See wiring diagram for the start- and control
unit for connection of the thermal fuse. A minimum
3
airflow of 500 N m /h is required in order to ensure
sufficient pump cooling.
Fig-