11
Maintenance and service guide - LSPX-FLSPX ZONE
21 - Ex tb – LSES-FLSES ZONE
22 - Ex tc
5725 en - 2020.02 / c
Positive temperature
coefficient thermistor
PTC
Non-linear variable
resistor,
indirectly heated
R
TNF
T
0
general surveillance
for transient overloads
Mounted with associated
relay in
control circuit
3 in series
Thermocouples
T
(T<150°C)
Constantan Copper
K
(T<1000°C)
Copper Copper-
Nickel
Peltier effect
V
T
0
high precision
of hot spots at
regular intervals
Mounted in control panels
with associated reading
equipment
(or recorder)
1 per hot spot
Platinum
temperature
sensor
PT 100
Linear variable
resistor
indirectly heated
R
T
0
high precision
continuous surveil-
lance
of key hot spots
Mounted in control panels
with associated reading
equipment
(or recorder)
1 per hot spot
- NRT: nominal running temperature.
- The NRTs are chosen according to the position of the sensor in the motor and the temperature rise class.
* The number of devices relates to the winding protection.
Alarm and early warning
All protective equipment can be backed up by another type of
protection (with different NRTs): the first device will then act as
an early warning (light or sound signals given without shutting
down the power circuits), and the second device will be the
alarm (shutting down the power circuits).
Protection against condensation: space heaters
Marking: 1 red label
A glass fibre flexible resistor is fixed on 1 or 2 coil end turns.
This resistor heats the machines when stopped and thus
prevents condensation inside the machines.
Power supply: 230 V single-phase unless otherwise specified
by the customer.
Recommended for use when ambient temperatures ≤ 20°C. In
all cases the power dissipated must ensure that the temperature
classification of the motor is observed.
Heaters or heating using the introduction of ac voltage must
only be used when the motor is de-energised and cold.
The drain plugs at the bottom of the motor must be opened
every six months or so. They must be refitted in place and the
motor degree of protection guaranteed.
Thermo-magnetic protection
Motors are protected by the magneto-thermal device placed
between the isolating switch and the motor. These protection
devices provide total protection of the motor against non-
transient overloads.
This device may be accompanied by fused circuit breakers.
Built-in direct thermal protections
For low rated currents, bimetallic strip-type protection may be
used. The line current passes through the strip, which shuts
down or restores the supply circuit as necessary. The design
of this type of protection allows for manual or automatic reset.
Built-in indirect thermal protection
Motors may be equipped with thermal sensors as an option.
These sensors follow the temperature changes at “hot spots”:
- overload detection,
- cooling check,
- monitoring characteristic points for maintenance of
the installation.
It must be emphasized that under no circumstances can these
sensors be used to carry out direct regulation of the motor
operating cycles.
The associated equipment must cause the motor to stop when
the values of the thermal protection indicated below are
reached
Thermal protection
In-line protection
Adjusting the thermal protection (see § 6)
It must be set to the current value shown on the motor nameplate
for the voltage and frequency of the connected supply.
Temperature sensor operating thresholds:
Maximum
temperature of
dust motor surface
Maximum value of the
winding sensor and of
adjustment of associated
equipment
Maximum value of the
bearing housing sensor and
of adjustment of associated
equipment
Frame size
(F)LSPX
80 to 250
(F)LSPX
280 to 355
(F)LSPX
80 to 250
(F)LSPX
280 to 355
85°C
120°C
100°C
90°C
70°C
100°C
120°C
110°C
90°C
90°C
125°C
130°C
140°C
110°C
110°C
135°C
130°C
140°C
110°C
110°C
145°C
130°C
140°C
110°C
110°C
Electrical characteristics of sensors and thermocouples:
* I max = 5A.
* U max :
* for PT100 at 0°C = 2.5 V * for PTO/PTF = 7.5 V
* for PTC = 7.5 V * for thermocouple = 7.5
V
In order to meet requirements for maximum surface
temperature, the thermal sensors fitted to the
motor must be connected to a device which causes the
supply to the motor to be cut off when the operating
thresholds defined above are reached.
INSTALLATION AND MAINTENANCE - LSPX-FLSPX ZONE 21 - Ex tb – LSES-FLSES ZONE 22 - Ex tc
