Main Components; Overview; Connections; Start-Up Valve - Nederman VAC 20 Manual De Instrucciones

4

Main components

4.1

Overview

Figure 1 shows the main components of the VAC 20 unit. These are as follows:
1.
Acoustic enclosure.
2.
Motor.
3.
2-stage high pressure fan.
4. Start-up valve. SUV 200 which also serves as a back flush valve. 24 V DC is supplied as
standard but a solenoid for 24 V AC is also enclosed.
5.
Anti surge valve. (TVS76, Control motor and silencer).
6. VAC 20-1500/2500/3000: Flow restrictor FR 160, see also Figure 4.
7. Manual reset thermal switch for the fan bearings.
8. Belt transmission.
The optional inlet silencer is shown in Figure 2.
1. Optional: Inlet silencer for extra low noise levels indoors.
4.2

Connections

Figure 5 is a schematic diagram of the normal connections to a VAC unit. Figure 5 shows the
normal connections to VAC 20. These are as follows:
1.
Exhaust duct.
2. Vacuum pipe from dust collector.
3. Dirt and water separator for compressed air. The separator is supplied with unit.
4. 6 mm (1/4") tube air line to start-up valve. The line is supplied with unit.
5. Control cable for start up valve, thermal switches and ASC damper.
6.
Optional: Control cable for when not using ASC by PLC.
7.
Motor power supply.
8.
Optional: Maintenance switch. This is required in most countries.
9.
Start and control unit normally with Y/D-starting. Direct starting is also an option.
10.
Terminal box
11.
Optional: ASC terminal box for when not using ASC by PLC. Sold as an accessory.
4.3

Start-up valve

Figures 6 and 7 show a circuit diagram for the control of the start-up valve. The solenoid
valve V1 is engaged only after the start and control unit has switched over to D-mode. The
valve needs compressed air to work.
4.4

Flow restrictor FR 160

A flow restrictor, FR 160, is mounted close to the fan outlet on most VAC 20 units, see
Figure 4. The restrictor protects the motor from overloading by gradually closing a valve
restricting the air flow.
The flow restrictor is fully mechanical. It consists of a valve blade, Item 1, welded to a shaft,
Item 3. The shaft turns in ball bearings fitted to the housing, Item 2. The spring, Item 6,
holds the blade in the normal open position.
VAC 20 EN
19