Gearbox Protection; Overload Relays; Starting Method - Grundfos SRP Instrucciones De Instalación Y Funcionamiento

7.2 Gearbox protection

The gearbox is monitored for the ingress of water by a leak
sensor incorporated in the gearbox.
If the monitoring function is required, the leak sensor must be
connected to a Grundfos relay, type ALR 20. If the gearbox/shaft
seal housing is not monitored for the ingress of water, it is
recommended to make inspection every 6 months. If oil is
contaminated by water replace shaft seal.
The cable between the relay and the pumps must
Note
Note
be maximum 164 ft (50 m).
For longer distance, use an additional, screened cable.
An external alarm indicator, if any, must be connected to the
potential-free outputs, terminals 1 and 3 or 4, respectively.
Maximum load: 250 V, 5 A.
Leak sensor
• Two conductors (terminals 21 and 22).
• Operating voltage: Approx. 12 V.
• Current: 1 to 10 mA.
To adjust the sensitivity of the ALR-20/A relay, proceed as
follows:
1. Turn adjusting screw (pos. a) on the relay until indicator light
(pos. b) illuminates.
2. Turn the adjusting screw in the opposite direction until the
indicator light goes out.
3. Continue to turn the adjusting screw 60 °
(same direction as in step 2).
2 10 4 1
A1 A2
Netz
Netz 230V 40-60Hz P3VA
Rel. Ue 400V le 2.5A AC15
a
5 7
Fig. 14 Adjusting the relay
12
3
Rel.
b
ALR 20/A
2 10 4 1
A1 A2
Netz
arnold ag
CH - 6105 Schachen
A Grundfos Company
Lecksonden Relais
Netz 230V 50-60Hz P3VA
II (2)G [EEx ib] IIC
nur für den Anschluss von Arnold AG
Lecksonden Typ AL05 Ex
Schaltpunkt
ALR 20/A Ex
SEV 05 ATEX 0131
Sonde
5 7
Sensor
Fig. 15 ALR 20 relay connections
Do not check the leak sensor with an ohmmeter
Note
Note
or other measuring instruments. The leak sensor
is an electronic component.

7.3 Overload relays

The motor must be protected against overload via a thermal delay
relay according to local regulations. The relay must be adjusted
to the rated current stated on the nameplate.
Electro-thermal all-pole triggers in all six mains conductors
(U1, V1, W1 and U2, V2, W2).

7.4 Starting method

In general it is advisable to use Soft-start or Variable speed drive,
in order to lower wear and tear on the equipment.
Continuous operation
The SRP recirculation pumps can be started via direct starting.
Intermittent operation
The SRP pump can be started via direct starting, prerequisite that
the maximum number of start per hour is not exceeded. In order
to limit wear and tear on the equipment, it is recommended that
the SRP pump has to be started using either Soft-starter or
Variable speed drive.
3
Rel.
Storung
1258