Moisture Switches; Thermistors; Checking After Installation Of Pump; Pt100 Temperature Sensor - Grundfos S1 Instrucciones De Instalación Y Funcionamiento

6.10 Moisture switches

Non-explosion-proof pumps have one moisture switch, which is
fitted in the chamber below the motor top cover.
Ranges 50-58 and 66-70 explosion-proof-pumps have two
moisture switches, one below the motor top cover and one in the
stator housing in the bottom of the motor.
Range 62 has both moisture switches placed below the motor top
cover. Moisture switches and thermal switches are motor
protection devices which protect the motor from damage due to
moisture or overheating. The moisture switches are
non-reversing and must be replaced after use.
The moisture switches and thermal switches are connected in two
separate circuits and to the control cable. See 8. Electrical
connection. They are also to be connected to the safety circuit of
the separate pump controller.
The safety circuit for the moisture switch must
Caution
ensure that the pump cannot start if the moisture
switch becomes wet due to water ingress.
The motor-protective circuit breaker of the pump
controller must include a circuit which
Caution
automatically disconnects the power supply in
case the protective circuit for the pump is
opened.

6.11 Thermistors

Thermistors are available as an option.
The thermistors can be used as motor protection devices to
monitor stator temperature instead of thermal switches and must
be connected to the thermistor relay in the control cabinet.

6.11.1 Checking after installation of pump

1. Using a multimeter, check whether the circuit resistance
is < 150 Ω / thermistor.
2. Using a multimeter, check whether the insulation between
circuit and stator housing is outside the scale

(not measurable ).
3. Carry out similar measurements at the end of the supply
cable.
14

6.12 Pt100 temperature sensor

The Pt100 temperature sensor is available as an accessory or as
an FPV (Factory Product Variant) option.
The Pt100 sensor is primarily used for the monitoring of bearing
temperature, but it can also be used in the stator.
The bearing temperature monitoring is only
Note
Note
available as an option. It is not available for range
50 and 54.
The sensor resistance is
100 Ω at 32 °F (0 °C)
•
138.5 Ω at 212 °F (100 °C)
•
approx. 108 Ω at room temperature.
•
The following temperature limits are used:
• 194 °F (90 °C) - alarm for bearing temperature
• 266 °F (130 °C) - pump stop caused by high bearing
temperature
• 302 °F (150 °C) - pump stop caused by high stator
temperature.
At room temperature, the PT100 temperature sensor resistance is
approx. 100 Ω.
Warning
In case of overheating caused by wear, lack of
lubricant etc., the Pt100 sensor trips an alarm and
disconnects the power supply at a preset
temperature. Max. acceptable alarm temperature
in bearing sensors is 212 °F (100 °C) for the lower
bearing (shaft end) and 248 °F (120 °C) for the
upper bearing (range 58, 62, 66 and 70 only).
6.12.1 Checking after installation of pump
1. Using a multimeter, check whether the resistance at room
temperature is approx. 108 Ω.
2. Using a multimeter, check whether the insulation between
circuit and stator housing is outside the scale

(not measurable ).
3. Carry out similar measurements at the end of the supply
cable.
4. During pump check, the Pt100 sensor must be connected to a
recording device.