Description; Motors; Pumps; Switching Device (Ac-Powered Model) - Zehnder Pumpen ZFS 71.1 W Ex Betriebsanleitung

4. Description

4.1 Motors

The pumps ZFS 71
phase asynchronous motor. Temperature sensors, which function as temperature limiters, have been integrated
into each of the three motor windings. If the motor overheats for any reason, the bimetallic contacts respond to this
and the motor is switched off.
The motor is to be restarted solely by hand! However, the motor may only be restarted after an error analysis
has been conducted and the cause of malfunction has been eliminated.
The motors are certified by the BVS - Dortmund and have the following certificates of conformity:
BVS 05 ATEX E 028 X

4.2 Pumps

The pump housing and the impeller are made of grey cast iron; the cutting device, which is located in front of the
impeller on the suction side, is made of a special alloy. This cutting device comminutes suspended soils, so that
they will not enter the pump and choke it. The pumps are equipped with a flange DN 50.
4.3 Switching device
The pumps are delivered without switching device.

5. Installation

- Disconnect the power supply before carrying out any kind of work on the plant!
- The electrical connections are not to be exposed to humidity!

5.1 Electrical equipment

The AC-powered model of the pump can be operated with an auxiliary switch device which is equipped with the
following elements:
main switch, fuses, contactors, thermal motor protection relay, operating capacitor, restart lockout for the clipping
circuit, signal lamps „Betrieb" (operation) and „Störung" (malfunction), Ex i - relay and a floater for the protection
against dry running.
The pump is connected to an earthed wall socket with an earthed type plug by means of the cable which is
connected to the switching device.
- The switching device has to be installed outside the explosion-prone area!
- The floater for the protection against dry running has to be installed in such a way, so that a decline of
the water level below the bottom line of the motor housing is not possible.
Further electrical installation is not necessary. If required, the motor housing can additionally be earthed by means
of the external earthing terminal intended for that.
II 2G EEx d IIB T3 are equipped with an AC asynchronous induction motor or a three-
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