1. Precautions for electrical test
(1) Be sure to turn the key switch to the OFF position before disconnecting or connecting the connector.
(2) Do not pull the wire to disconnect the connector, hold the connector and pull it apart.
(3) Most connectors are made of brass. Before connecting the connector, check whether the connector terminal is straight, and check whether the terminal is damaged or rusty.
(4) Before using the circuit tester, please refer to the instructions in the circuit tester manual. Then, adjust the circuit tester to meet the measurement voltage range and current polarity.
(5) Before connecting the connector test, always check the number of the connector terminal, see the circuit diagram.
When the size of the connector is very small, the standard probe is too large for testing. At this time, a thin, polished wire or needle can be wrapped around the probe to make the test easier.
2, 3 basic forms of wire inspection
(1) Measure the resistance of the circuit tester with an ohmmeter to check the continuity of the circuit.
(2) Use a voltmeter to measure the voltage of the circuit tester and check whether the voltage in the circuit meets the regulations.
(3) Check the controller function by giving a false signal instead of the sensor signal. To do this, short the connector and send its voltage directly to the controller.
3, continuity check
(1) Single-line continuity check. Disconnect the connectors at both ends of the wire and check the continuity at both ends: the ohmmeter reading is 0Q-continuous; the ohmmeter reading is ∞-discontinuous.
Note: When one end of the connector is far away from the other end, use a wire clamp to connect one end of the connector (A) to the machine frame, and then check the continuity of the wires passing through the machine frame. The reading of the ohmmeter is 0n- -continuous; the reading of the ohmmeter is ∞-discontinuous.
(2) Single wire short circuit check. Disconnect the connectors at both ends of the wire and check the continuity between the wire-end connector and the machine frame. If the ohmmeter reads 00, there is a short circuit; if the ohmmeter reads ∞, there is no short circuit.
(3) Multi-line continuity check. Disconnect the connectors at both ends of the wire, short-circuit the two terminals A and B at one end of the connector, and then check the continuity between the connector terminals a and b. If the ohmmeter reads ∞.
then the line A- -a or B-b is not continuous. In order to find out which wire is not continuous, perform a single-wire continuity check on the two wires, or change the short-circuit terminals from A and B to A and c, and then check the secondary terminals a and. The continuity between.
Note: Through two multi-line continuity checks, you can find out which line is not continuous. Short-circuit between terminals A and e, and check the continuity between terminals a and c. The reading of the ohmmeter is 00-line B-b is discontinuous; the reading of the ohmmeter is ∞, the line A-a is discontinuous.
(4) Multi-line short circuit check. Disconnect the connectors at both ends of the wire and check the continuity between terminals A and B or C. The reading of the ohmmeter is 0N-there is a short circuit between the two terminals; the reading of the ohmmeter is ∞--there is no short circuit between the two terminals.
Note: For connectors, circuit diagrams and wiring diagrams, see the electrical system section.
