Fouling status

1 . A computer-implemented method comprising:

receiving a first temperature value indicating a temperature near a heat source, a second temperature value indicating a temperature near an outer end of a cooling rib extending from the heat source, and a third temperature value indicating an ambient temperature in the location of the heat source;

determining, using at least the received first, second and third temperature values, a convection rate indicator value;

determining, using the convection rate indicator value, fouling status of cooling ribs cooling the heat source; and

triggering a maintenance alert when the fouling status is dirty.

2 . The method of claim 1 , wherein the determining the fouling status comprises:

comparing the convection rate indicator value to a preset threshold; and

determining that the fouling status is dirty when the convection rate is below the preset threshold.

3 . The method of claim 1 , further comprising:

determining the convection rate indicator value using a distance between measurement points of the first and second values.

4 . The method of claim 1 , further comprising:

maintaining information on whether a dirty status has been set;

when the dirty status has not been set, performing determining the convection rate indicator value and the fouling status; and

setting, when triggering the maintenance alert, the dirty status.

5 . An arrangement comprising at least:

a heat source;

a plurality of cooling ribs, extending from the heat source, arranged to cool the heat source;

a first temperature sensor near the heat source to measure first temperature values;

a second temperature sensor near an outer end of a cooling rib, at a distance from the first temperature sensor to measure second temperature values;

an ambient air temperature sensor to measure third temperature values in an environment at a location the heat source is; and

a fouling status determination unit configured to obtain the first temperature values, the second temperature values and the third temperature values to determine fouling status of the cooling ribs.

6 . The arrangement of claim 5 , wherein the fouling status determination unit is configured to:

determine convection rate indicator values using at least the first temperature values, the second temperature values, and the third temperature values;

determine, using the convention rate values, the fouling status; and to trigger a maintenance alert when the fouling status is determined to be dirty.

7 . The arrangement of claim 5 , further comprising:

a slat between two cooling ribs, wherein the first temperature sensor and the second temperature sensors are attached to the slat.

8 . The arrangement of claim 7 , wherein the slat is a hollow metal casing, and the first temperature sensor and the second temperature sensor are embedded in the hollow metal casing.

9 . The arrangement of claim 5 , wherein the fouling status determination unit is configured to obtain the temperature values periodically.

10 . The arrangement of claim 5 , wherein the heat source is an electric motor within a motor frame and the plurality of cooling ribs are extending from the motor frame, arranged to cool the electric motor.

11 . The arrangement of claim 10 , further comprising a terminal box for the electric motor, wherein the ambient air temperature sensor is attached to the outer surface of the terminal box.

12 . The arrangement of claim 10 , further comprising a motor controller unit connectable to the temperature sensors and including the fouling status determination unit.

13 . The arrangement of claim 5 , further comprising:

a micro controller unit connectable to the temperature sensors for obtaining the temperature values; and

a remote control unit connectable to the micro controller unit to obtain the temperature values, the remote control unit including the fouling status determination unit.

14 . An apparatus comprising:

at least one interface configured to receive a first temperature value indicating a temperature near a heat source, a second temperature value indicating a temperature near an outer end of a cooling rib extending from the heat source, and a third temperature value indicating an ambient temperature in the location of the heat source;

at least one processor; and

at least one memory storing instructions,

wherein the at least one memory and the instructions configure, with the at least one processor, the apparatus at least to:

determine, using at least the received first, second and third temperature values, a convection rate indicator value;

determine, using the convection rate indicator value, fouling status of cooling ribs cooling the heat source; and

trigger a maintenance alert when the fouling status is dirty.

15 . The apparatus of claim 14 , wherein the at least one memory and the instructions configure, with the at least one processor, the apparatus to determine the fouling status at least by:

comparing the convection rate indicator value to a preset threshold; and

determining that the fouling status is dirty when the convection rate indicator value is below the preset threshold.

16 . The apparatus of claim 14 , wherein the at least one memory and the instructions configure, with the at least one processor, the apparatus to determine the convection rate indicator value using also a distance between measurement points of the first and second values.

17 . The apparatus of claim 14 , wherein the at least one memory and the instructions configure, with the at least one processor, the apparatus at least to:

maintain information on whether a dirty status has been set;

when the dirty status has not been set, perform determining the convection rate indicator value and the fouling status; and

set, when triggering the maintenance alert, the dirty status.

18 . The apparatus of claim 14 , wherein the apparatus is a micro controller unit.

19 . The apparatus of claim 14 , wherein the apparatus is a portable user device.

20 . The apparatus of claim 14 , wherein the apparatus is a server in a service center, which is remote to the heat source.