AS/NZS IEC 60947.5.9:2015 pdf download – Low-voltage switchgear and controlgear Part 5.9: Control circuit devices and switching elements- Flow rate switches.
3.2 Classification according to sensing means
In this standard the sensing means is designated by a capital letter placed in the first position.
3.3 Classification according to the construction form
The construction form is designated by a one-digit number placed in the second position.
3.4 Classification according to the switching element function
The switching element function is designated by a capital letter placed in the third position.
3.5 Classification according to the type of output
The type of output is designated by a capital letter placed in the fourth position.
3.6 Classification according to the method of connection
The method of connection is designated by a one-digit number placed in the fifth position.
4 Characteristics
4.1 Summary of characteristics
4.1.1 General
The characteristics of flow rate switches shall be stated In the followIng terms:
— Operating conditions (4.2)
— Rated and limiting values (4.3)
Rated voltages (4.3.1)
Currents (4.3.2)
Rated supply frequency (4.3.3)
Normal load and abnormal load characteristics (4.3.4)
Short-circuit characteristics (4.3.5)
— Utilisation categories for the switching element (4.4)
4.1.2 Operation of a flow rate switch The output state is determined by
— the rate of flow in the active zone of the flow sensor, and
— the set point(s).
4.2 Operating conditions
4.2.1 Operating points of a flow rate switch
The relationship between the operating points is shown in Figure 1.
4.3.1 .3 Rated impulse withstand voltage (U imp ) Subclause 4.3.1 .3 of IEC 60947-1 applies. 4.3.1 .4 Voltage drop (U d ) The voltage drop is the voltage measured across the active output of the flow rate switch when carrying the rated operational current under specified conditions. The values are specified in 7.2.1 .1 3. 4.3.2 Currents The switching element of a flow rate switch is defined by the following currents. 4.3.2.1 Rated operational current (I e ) See 7.2.1 .9. 4.3.2.2 Minimum operational current (I m ) See 7.2.1 .1 0. 4.3.2.3 OFF-state current (I r ) See 7.2.1 .1 1 . 4.3.2.4 No-load supply current (I o ) The maximum no-load supply current of a three- or four-terminal flow rate switch shall be stated by the manufacturer. 4.3.3 Rated supply frequency The rated supply frequency for a.c. flow rate switches shall be 50 Hz and/or 60 Hz. 4.3.4 Normal load and abnormal load characteristics 4.3.4.1 Rated making and breaking capacities and behaviour of switching element under normal conditions A semiconductor switching element shall comply with the requirements given in Table 4 of IEC 60947-5-2. NOTE For a semiconductor switching element to which a utilization category is assigned, it is not necessary to specify separately a making and breaking capacity. 4.3.4.2 Making and breaking capacities under abnormal conditions A semiconductor switching element shall comply with the requirements given in Table 5 of IEC 60947-5-2. NOTE For a semiconductor switching element to which a utilization category is assigned, it is not necessary to specify separately a making and breaking capacity. 4.3.5 Short-circuit characteristics The rated conditional short-circuit current of a flow rate switch is 1 00 A prospective. The flow rate switch shall withstand satisfactorily the test specified in 8.3.4.
6.1 .4 Climatic conditions 6.1 .4.1 Humidity The relative humidity (RH) of the air shall not exceed 95 %. 6.1.4.2 Pollution degree Unless otherwise stated by the manufacturer, a flow rate switch is intended for installation under environmental conditions of pollution degree 3 as defined in 6.1 .3.2 of IEC 60947-1 . However, other pollution degrees may apply, depending upon the micro-environment. 6.2 Conditions during transport and storage A special agreement shall be made between the user and the manufacturer if the conditions during transport and storage, e.g. temperature and humidity conditions, differ from those defined in 6.1 . 6.3 Mounting Mounting dimensions and conditions shall be stated by the manufacturer. 6.4 Indicating means Flow rate switches may have one or more coloured indicating means. If applicable they shall have the following meaning: a) green (constant) power ON; b) yellow (constant) switching element ON; c) red (constant) failure indication; d) any other colour (constant) or one of the above mentioned colours (flashing): other functions (e.g. short-circuit indication). 7 Constructional and performance requirements 7.1 Constructional requirements 7.1.1 Materials Subclause 7.1 .1 of IEC 60947-5-2 applies. 7.1.2 Current-carrying parts and their connections Subclause 7.1 .2 of IEC 60947-1 applies. 7.1.3 Clearances and creepage distances Subclause 7.1 .3 of IEC 60947-1 applies. 7.1.4 Actuation Flow rate switches are tested for operation by adjusting the rate of flow of a medium specified by the manufacturer across the set point for both increasing and decreasing flow rates.