7.2.3 Integrated starting switches, speed controls, etc.
整体式启动开关、速度控制器等
For starters, speed controls etc. incorporated in appliances like sewing machines and similar apparatus given in Table A.2 the second paragraph of 7.4.2.3 applies.
7.2.3.1 Starters and speed control of sewing machines and dental drills. To determine the disturbance generated during starting and stopping the speed of the motor shall be increased to maximum speed over a 5 s period. For stopping, the control shall be reset quickly to its off position. To determine the click rate N, the period between two starts shall be 15 s.
7.2.3.2 Starting switches in adding machines, calculating machines and cash registers shall be operated intermittently with at least 30 starts per minute. If 30 starts per minute cannot be attained, then intermittent operation with as many starts per minute as possible in practice shall be used.
7.2.3.3 Picture change devices of slide-projectors. To determine the click rate N, the device shall be operated with the lamp switched on and with four picture-changes per minute without slides.
Thermostats for, or integrated in permanently installed room heating equipment intended for stationary use shall be allocated with a click rate N which is five times the click rate determined for a single, portable or removable room heater.
The click rate N shall be determined for the maximum operating rate stated by the manufacturer or – if sold for or together with a heater or burner – for a duty-cycle of (50 ± 10) % of this heater or burner.
The amplitude and duration of the disturbance shall be measured for the lowest rated current of the thermostat. For thermostats which have an acceleration resistor incorporated, the same measurements shall be performed in addition, without any separate heater connected.
When, in practice, the thermostat may be used together with inductive loads (e.g. relay,contactor) all measurements shall be performed using such a device, having the highest coil inductance used in practice.
In order to obtain a satisfactory measurement, it is essential that the contacts shall be operated for a sufficient number of times with a suitable load to ensure that the levels of disturbance are representative of those encountered in normal operation