Usage and operating procedures of high and low pressure clamp gauges
1. When using a high-voltage clamp meter, attention should be paid to the voltage level of the clamp ammeter. It is strictly prohibited to use a low-voltage clamp meter to measure the current of the high-voltage circuit. When using a high-voltage clamp meter for measurement, it should be operated by two people. Non duty personnel should also fill out the second type of work permit. When measuring, they should wear insulated gloves, stand on insulated pads, and not touch other equipment to prevent short circuits or grounding.
2. When observing the timing of the watch, special attention should be paid to maintaining a safe distance between the head and the charged part. The distance between any part of the human body and the charged part should not be less than the entire length of the clamp watch.
3. When measuring on a high-voltage circuit, it is prohibited to connect wires from a clamp ammeter to another meter for measurement. When measuring the current of each phase of high-voltage cables, the distance between cable heads should be at least 300mm, and the insulation should be good. It can only be carried out when it is considered convenient for measurement.
4. When measuring the current of low-voltage fusible fuses or horizontally arranged low-voltage busbars, each phase of the fusible fuse or busbar should be protected and isolated with insulation materials before measurement to avoid causing phase to phase short circuits.
5. It is strictly prohibited to measure when one phase of the cable is grounded. To prevent ground breakdown and explosion caused by low insulation level of cable heads, which may endanger personal safety.
6. After the clamp ammeter measurement is completed, turn the switch to the maximum range to avoid overcurrent during the next use; And should be stored indoors in a dry place.
A clamp meter is an instrument that combines current and ammeter, and is an important branch of digital technology. Its working principle is the same as measuring current. A clamp meter is a combination of a current transformer and an ammeter. The iron core of the current transformer can be opened when the wrench is tightened; The wire through which the measured current passes can pass through the open gap of the iron core without cutting it off, and the iron core closes when the wrench is released. The tested circuit wire passing through the iron core becomes the primary coil of the current transformer, and the current is induced in the secondary coil through the current. So that the ammeter connected to the secondary coil has an indication - to measure the current of the tested circuit.
A clamp meter is essentially composed of a current transformer, a clamp wrench, and a rectifier magneto electric system reactive force instrument.
The working principle of a clamp type meter is the same as that of a transformer. The primary coil is a wire that passes through a clamp type iron core, which is equivalent to the primary coil of a 1-turn transformer. This is a step-up transformer. The secondary coil and the ammeter used for measurement form the secondary circuit. When there is AC current passing through the wire, it is the alternating magnetic field generated by this coil, which induces current in the secondary circuit. The magnitude of the current is proportional to the proportion of the primary current, which is equivalent to the inverse ratio of the number of turns in the primary and secondary coils. A clamp type ammeter is used to measure large currents. If the current is not large enough, the number of turns of a wire passing through the clamp type ammeter can be increased, and the measured current can be divided by the number of turns.
The secondary winding of the through core current transformer of the clamp ammeter is wound around the iron core and connected to the AC ammeter. Its primary winding is the measured wire passing through the center of the transformer. The knob is actually a range selection switch, and the function of the wrench is to open and close the movable part of the core of the through core transformer, so as to clamp it onto the measured wire.cannot see the internal situation and cannot dismantle a large number of components like mechanical components. By utilizing logic and reasonable steps, problems can be quickly identified. The key tool in this process is the multimeter.
The class nature of signals
The tested signals mainly include voltage, current, and resistance. But the most commonly used is voltage. The issues involved include: Is there voltage present? What is the voltage value? What should be the normal value? What is the voltage drop of the component or connection point? For example, if the input voltage of a relay is 12.8V and the output terminal is 9.2V, the voltage drop is 3.6V. Please note that the joints of the wires should be considered as components and will generate voltage drops. So it may also cause malfunctions.
Diagnosis of faults in automobiles using analog/digital multimeters
According to different systems, electrical faults in cars can be divided into several categories. Please note that the actual fault may occur in one system, while the test phenomenon may occur in another system. The systems covered by this manual mainly include: charging systems; Starting system; Fuel/air system; Ignition system; Body/engine management/cold system.
Most people do not take a car to a repair shop until it cannot start. The driver is the first to see the malfunction. So the biggest challenge is to determine which system is causing the inability to start. Some faults are formed by long-term accumulation, such as repeated electricity, difficulty starting on hot days, etc. Once the system that may cause a malfunction is identified, it can be tested using a Fluke multimeter.
