Homa MX-ET Serie Originalbetriebsanleitung Seite 32

Triggering temperature of the temperature monitor-
ing/sensors:
Motor Standard winding
T1+T3 controllers
AM210...ET 125°C
Control of direction of rotation
All pumps rotate in the correct direction when connected
to a field rotating clockwise (U, V, W -> L1, L2, L3). HOMA
switchgear checks that the field of the grid rotates clock-
wise. If there is no field rotating clockwise, the red LED
is lit. Two phases have to be exchanged at the input to the
switchgear. In smaller pumps, the check can be made by
observing the starting jerk. To do this, place the pump ver-
tically on the floor, slightly on edge, and switch on briefly.
Seen from above, the pump jerks slightly anticlockwise if
the direction of rotation is correct.
The direction of rotation of the pump is correct if the pump
moves anticlockwise because, seen from above, the mo-
tor starts in the clockwise direction.
ATTENTION
The direction of rotation
is correct if the
impeller/propeller rotates
in a clockwise manner
when viewing down from
top of the placed unit
In large pumps, the direction of rotation can also be rec-
ognized by looking through the discharge outlet into the
pump chamber.
The blade wheel is visible and, after briefly switching on,
its direction of rotation can be checked as it rolls to a stop.
Warning of rotating blade wheel!
Do not touch the rotating blade wheel or reach
through the discharge outlet into the pump chamber!
During operation, never reach into the pump cham-
ber or touch rotating parts. Before maintenance or
repair work, shut the machine off and let the rotating
parts come to a standstill!
It is also possible to check the direction of rotation with a
„motor and phase rotation indicator". This measuring in-
strument is held externally against the motor housing of
the running pump: it shows the direction of rotation with
an LED.
Seal monitoring for pumps with oil chamber:
If the shaft seal on the medium side leaks, water enters
the oil chamber and changes the resistance of the oil. The
conductivity of the oil added is monitored via 2 sensors.
The sensors should be connected via 2 wires (designated
S1 and S2) from the pump connecting cable in the con-
trol system to an evaluation unit with electrically isolat-
ed probe circuit. With the version for use in areas with a
potentially explosive atmosphere, select an electrode re-
lay with intrinsically safe circuit. The response sensitivity
should be adjustable from 0-100 kΩ; standard setting 50
kΩ. Appropriate relays can be purchased from HOMA.
32 | ENGLISH
Motor cooling
In all variant installations, the conveyed medium flows
around the motor and cools it.
Ex winding
3.3.4. Sealing / sealing casing
T1+T2 limiters
Sealing is effected with two slide ring seals made of sili-
125°C
con carbide operating independently in tandem. The seal-
ing casing is located between the motor and the pump
housing. It consists of the bearing housing and the pres-
sure lid, which together form the sealing space filled with
medical white oil. Checking is possible by means of the
inspection switch on the bearing housing and an optional
electronic monitoring system.
3.3.5. Pump Housing
The pump housing can be supplied, depending on design
and motor version with various DIN and ANSI flanges. That
produces an optimum connection to the various pipeline
types. The pump housing on the intake side is equipped
with a split ring. This split ring determines the size of the
gap between the impeller and the intake pipe. If this gap is
too large, the conveying power of the pump reduces and
it can quickly lead to blockages. Therefore, it is possible
ATTENTION
to replace the split ring to reduce the cost of spare parts.
The start reaction is
anti clockwise
3.3.6. Impeller
The impeller is fastened to and driven by the motor shaft.
It can be partly supplied in various types of material (cast
iron, high chrome iron, SGCI, SS, BZ) and may also be
coated in ceramic.
Furthermore, the impellers have the following construc-
tions:
M
K
V
OC
with enclosed single channel wheel, for dirty and muddy
conveying media with solid and long-fibre parts of up to 5%
with enclosed multi-channel wheel, for dirty and muddy
conveying media with solids of up to 3%
Free-flow wheel, for large and fibrous dirty, braid-forming
and gaseous conveying media of up to 7%
open multi-channel wheel with cutting edge, for dirty and
muddy conveying media with solids of up to 8%