AC contactor is a switch device that uses electromagnetic force to cooperate with spring force to realize contact on and off to control the on-off of load circuit. It is suitable for frequent operation and long-distance control, and is an important part of automatic control circuit system. element. With the growth of national economic demand and power industry, the demand for AC contactors continues to grow, and the competition is also increasingly fierce. In order to ensure product quality, the testing of AC contactors is particularly important.
The following will use a certain brand ofTaking the testing requirements of AC contactors as an example, we will introduce the AC contactor testing solutions provided by ITECH in detail:
Before starting the test, we first understand its working principle: when the attraction coil of the AC contactor is energized, the static iron core generates electromagnetic attraction, the armature is attracted, and the connecting rod connected to the armature drives the contact to move, so that the normally closed contact Disconnected, the normally open contact is closed, the two are linked, and the contactor is in the energized state; when the attracting coil is powered off, the electromagnetic attraction disappears, and the armature is released under the action of the spring, so that the normally closed contact is closed, and the normally open contact The head is disconnected, and the contactor is in a de-energized state;
The client test requirements are as follows:
1. ON/OFF test: set ON/OFF AC voltage (rated voltage), start angle 90°, end angle 0°, ON/OFF twice, and finally OFF.
2. Characteristic test: set voltage (rated voltage), start angle 30°, end angle 90°, output is ON, read peak current immediately, delay 500ms, read holding current, maintain power consumption, and finally OFF
3. Test of pull-in voltage: first set the pull-in starting voltage (20% of the rated voltage), the output is ON, and then every 200ms, the voltage rises in steps of 5V, after rising to pull-in, read the pull-in voltage, the last output is OFF
4. Release voltage test: first set the release starting voltage (rated voltage), the output is ON, after setting the release voltage (rated voltage 68%) and then every 200ms, the voltage will decrease in steps of 5V, and after it is released, Read release voltage; last output OFF
Solutions provided by ITECH:
The AC power supply of IT7321 can provide the rated working voltage for the AC contactor, and realize the connection and disconnection of the AC contactor.The connection circuit is shown in Figure 1:
Figure 1. IT7300 AC source test AC contactor example
Test requirements (1) (2) can be realized through the Panel setting function of IT7321. This function can set the voltage, frequency, starting phase angle and ending phase angle. The range of the settable phase angle is 0. -360︒
Test requirements (3) (4) can be achieved through the sweep function of IT7321, which can set the starting voltage value, ending voltage value, step voltage value, starting frequency, ending frequency and single step time, so that the voltage and frequency of the power supply are Step-by-step change, and after the test, the voltage, frequency and current parameters of the maximum power point can be displayed.
The above test requirements (3) Through the SWEEP function of IT7321, the waveform captured by the oscilloscope is shown in Figure 2:
Figure 2. IT7300 AC source measured sweep voltage and current waveforms
IT7300 programmable AC power supply series adopts advanced high-precision linear amplifier circuit design, which can provide low-noise and high-stability output. The adjustable phase angle function is suitable for all kinds of switching current impact tests and debugging rectifiers. The sweep function is used in Efficiency test of various power Electronic products, and can capture the voltage and frequency values of the maximum power point. In addition, the dimming and speed controller simulation functions can perform dimming and speed regulation tests on lamps and motor products to verify products. Judging whether there is a safety hazard when the end user uses the dimming or speed control controller; the interference simulation function of the input power supply can simulate instantaneous power interruption, surge, notch, specific phase angle on or off, AC Sine wave amplitude and frequency rise and fall slowly. Products have been widely used in electronic motor industry, lighting, aviation, military industry, as well as research and development quality inspection units and factory production line testing and other fields.
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