The good or bad of conductivity of breaker(hereinafter referred to as switch) conductive circuit, play an important role in guarantee the safety operation of switch. The conductivity performance can be reflected by the value of conductive circuit resistance. For this reason IEC standard and manufacturers all required testing the circuit resistance, and also have prescribed index for the circuit resistance of each kind switch. Before, normally use double bridge. But, because the voltage and current value are very small, when there are impurities between dynamic and static contact or the contact got surface oxidation, the dispersivity of test data is larger. At the same time, the anti-interference performance of bridge is not good, so the national standard requires that must test with DC more than 100A. The circuit resistance tester is a product developed by our company which in order to meet GB50150-2006 and DL/T 845.4-2004 regulations, and it was widely used in measurements of various switch’s contact resistance、circuit resistance, cable and wire、weld joint contact resistance.

1、Operator must have common sense to operate electrical equipment or instrument.

2、Please read operating manual carefully before use this instrument.

3、The adjustment and maintenance of the instrument must be done by specialized persons, don’t fix by yourself.

4、The instrument should avoid strenuous vibration, avoid heat and direct sunlight.

5、This instrument was designed to test purely resistive circuits, can not use to test inductive circuits.

6、Can’t dismantle test wire during test.

7、The grounding wire must connect correctly.

1、The test current value is big, completely conform the national standard requirement which related to contact resistance test.

2、The test current was came from the 500A/600A high precision switch type constant current power supply, without manual adjust, the test is rapid and accurate.

3、Adopt four terminal connections; effectively eliminate the influence to the test result from resistance of test wire.

4、Test speed is fast, the USB interface can connect with PC, upload test data.

5、Working long hours, equipped with overheat protection circuit; the instrument is reliable and steady.

6、Easy and simple operation, light weight.

1、 Test Current ：

2、 Testing range：

3、Minimum resolution ：0.01μΩ

4、Accuracy ：0.5%±0.5μΩ

5、Power supply ：AC220V±10％ 50Hz

6、Consumed power ：

7、Operating temperature ：-20℃～40℃

9、Relative humidity ：≤80%RH， non-condensate

1、What is contact resistance?

Contact resistance is the additional resistance when the static contact touch dynamic contact.

2、Breaker contact resistance was made up of which part?

Was made up of contract resistance and surface resistance of dynamic、static contact area.

3、Unqualified reasons of breaker contact resistance?

— Contact burn out when switch big short circuit current.

— When the construction adjust not good or fixed not securely, cause change stroke, when over stroke was badly unqualified, cause contact pressure and contact area changed.

— After adjustment and installation of breaker, not operate for a long time, cause dynamic、static contact got surface oxidation, contact area resistance increase.

— Long-time working cause spring deformation, decrease the contact pressure.

—Mechanical wear of mechanical part after long-time working.

—For low-oil breaker, also can be the reason of unqualified acid value of insulating oil, when it appear acid and corrode the surface. Or because of the floating impurities in oil, and tiny carbon、metal dust between dynamic、static contact caused by switch short circuit current, can increase the contact resistance.

4、The factors influencing resistance.

—Material property: hardness、chemical property、mechanical strength and electrical resistivity of metallic compound.

—Contact mode: point contact、line contact、surface contact.

—Contact surface situation: when the contact surface form oxidation film(except silver),the resistance of oxidation film is much bigger than the metal.

—Contact pressure.

—Roughness of contact surface.

After-sales service

1. Our company gives one year warranty for sold product. If user wants maintenance please contact our after-sales department.

2. During warranty period if happen any following situation, we will charge a cost price for maintenance:

1） Failure or damage caused by clash during user using or moving the product.

2） The product was not kept properly by user, cause instrument ooze water、affected with damp、clash or light fire and so on.

3） Failure or damage caused by maintenance from user or other entrusted unit by user.

4） Failure or damage caused by wrong connection from user.

5） Failure or damage caused by force majeure(like fire disaster、flood disaster、natural disaster and so on)

6） Failure or damage caused by connect to other equipment not according to this manual.

7） Faulty product has no warranty card and unable to determine it is within warranty period.