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6.2 Gearbox or shaft seal housing protection
The gearbox or shaft seal housing is monitored for the ingress of
water by means of a leakage sensor incorporated in the gearbox
or shaft seal housing.
If the monitoring function is required, connect the leakage sensor
to a leakage relay. A relay can be ordered as an accessory.
If the gearbox or shaft seal housing is not monitored for the
ingress of water, we recommend that you make inspections every
6 months. If the oil contains water, replace the shaft seal.
The cable between the relay and the mixer or
flowmaker must not be longer than 164 ft (50 m).
For a longer distance, use an additional, screened cable. Always
connect an external alarm indicator, if fitted, to the potential-free
outputs, terminals 1 and 3 or 4. Maximum load: 250 V, 5 A.
If you need to lengthen the power cable to the
sensor, comply with the FM directive as well as the
ANSI/ISA 60079-0 and ANSI/IEC 60079-14
standards for the intrinsically safe circuit.
The terminal connections of the intrinsically safe and
FM
the non-intrinsically safe circuits must be separated
and be clearly distinguishable.
The operator must make sure that all installation
work is done in conformity with the relevant
standards.
When the leakage relay is connected, a current of up to 10 mA
flows through the leakage sensor. Terminals 5 and 7 in fig.
connected to wires 21 and 22 in fig. 25. In case water penetrates
into the oil chamber, the relay will trigger an alarm signal and/or
switch off the motor. See fig.
25
Leakage sensor
•
Two conductors, wires 21 and 22.
•
Maximum operating voltage: Approx. 12 V.
•
Maximum current: 1 to 10 mA.
•
Standard SMD mixer equipped with leakage sensor and wiring
connections
DANGER
Electric shock
Death or serious personal injury
- When adjusting the relay, beware of electric
voltage.
Do not check the leakage sensor with an ohmmeter
or other measuring instruments. The leakage sensor
is an electronic component.
16
32
are
or 26.
Moisture switch
A moisture switch is built into each SMD mixer. The moisture
switch monitors the motor housing and is located in the non-drive
end of the motor housing. If moisture appears, the switch will be
triggered and cause the power to the SMD to be cut out.
Overload relays
Protect the motor against overload via a thermal delay relay
according to local regulations. Adjust the relay to the rated
current stated on the nameplate.
In the case of star-delta starting, the adjustable value is to be 58
% of rated current.
Incorporate electro-thermal all-pole triggers in all six mains
conductors (U1, V1, W1 and U2, V2, W2).
6.3 Starting method
6.3.1 SMD
Continuous operation
You can use direct-on-line starting throughout the entire power
range.
Intermittent operation
We recommend that you use a soft starter or a frequency
converter for motors of 3 hp (2.2 kW) and higher.
6.3.2 SMG
Continuous operation
You can use direct-on-line starting for motors up to 2.2 hp (1.6
kW).
We recommend that you use star-delta starting, soft starter or a
frequency converter for motors of 2.7 hp (2.0 kW) and higher.
Intermittent operation
We recommend that you use a soft starter or a frequency
converter throughout the entire power range.
6.3.3 SFG
Continuous operation
We recommend that you use star-delta starting, a soft starter or a
frequency converter.
Intermittent operation
It is mandatory to start flowmakers in intermittent
operation via a soft starter or a frequency converter.
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