Contact Resistance Tester | MT-DCRT1100

MT-DCRT1100; It is a portable contact transition resistance meter designed for measuring circuit breakers, switching equipment, busbars and any low resistance using adjustable DC test current between 5A ~ 100A according to IEC 61010-1 and IEC 61326-1 standards. It has current measurement feature and display. It performs contact resistance measurement operations with high accuracy.

• Adjustable DC Current Between 1-100
• 3.5″ Touchscreen Color HMI Display
• 4-Lead Measurement Method
• Included Printer
• Accuracy ±(0.01%)
• Industrial Rugged Case

ELECTRICAL PARAMETERS

TECHNICAL PARAMETERS

What is Contact Resistance?

Contact resistance is the resistance to current flow when the contacts touch each other (when the device is in the off state) due to surface conditions and other reasons.

Where Does Contact Resistance Occur?

• Cutters
• Contactors
• Relays
• Keys
• Connectors
• Other Switching Devices

What Problems Does the Contact Resistance Test Detect?

It is used to measure resistance in different applications of electrical testing. Consisting of a DC ammeter and several other components, this tester detects the following issues;

• Loose connections
• Sufficient tension on bolted connections
• Worn contact surfaces
• Dirty or worn contacts

Why is Contact Resistance Test Necessary?

The contacts on the circuit breaker need to be checked periodically to ensure that the breaker is healthy and functional. Poorly maintained or damaged contacts can cause sparks, loss of phase or even fire. Measuring contact resistance helps identify corrosive corrosion of contacts and allows diagnosis and prevention of contact corrosion. An increase in contact resistance can cause a high voltage drop in the system and this needs to be controlled.

What is done during the contact resistance test?

Two common checks performed on the contacts of a circuit breaker are visual inspection check and contact resistance check.

Visual inspection check includes inspecting the contacts of the circuit breaker for any signs of pitting due to arcing and worn or deformed contacts.
The second check is the contact resistance measurement. This involves injecting a constant current, usually around 100A, through the contacts and measuring the voltage drop across it. This test is done with a special contact resistance measuring device. Then the tester calculates the resistance value. The resistance value read on the device should be compared with the value given by the manufacturer. The value should also be compared with previous records.

Both of these tests need to be done together. Because the contacts have good contact resistance and can also be damaged. Therefore, to be considered reliable, a contact must have good contact resistance and pass a visual inspection test.