DLRO10HD Dual Power
10A Low Resistance Ohmmeter

Description
The DLRO10HD combines ultimate simplicity of operation with a rugged IP65 case designed for stable ground and bench operation. The unit is powered from either its internal rechargeable battery or line power making it suitable for continuous testing in production line/repetitive use environments.

Rotary switch controls are simple and easy to operate in all weather conditions and with gloved hands. A large, clear, backlit LCD display is easy to read from a distance.

The DLRO10HD provides significantly enhanced compliance and is capable of delivering 10 amps into measurements up to 250mΩ and 1 amp into measurements up to 2.5Ω. The duration of each test may be up to 60 seconds. The instrument is rated CAT III 300V. A range of test leads is available to suit the application.
 

• High or Low output power selection for condition diagnosis.
• Rechargeable battery or line power supply. Continuous operation, even with dead battery when connected to line power.
• 10A for 60 seconds, less time waiting to cool, great for charging inductance.
• High input protection to 600volts, inadvertent connection to line or UPS voltage will not blow a fuse.
• Heavy duty case: IP65 lid closed, IP54 operational (battery operation only).
• Rotary switch selects one of five test modes, including auto start on connection, giving ease of use.

• Rugged case well suited to transportation with shoulder strap and test lead set pouch.
• Removable lid facilitates easy test lead connection.
• Operational ingress protection is IP54 (battery power only) ensuring protection from the elements.
• 7AH lead acid battery provides extended operation and can be charged whilst operating from line power.
• Rotary mode switch with bidirectional (current reversal with averaging cancels thermal EMF's), unidirectional, automatic, continuous and inductive modes.
• Large, clear LCD display with backlight and contrast adjustment.
• Auto power OFF function conserves battery.

Applications and Test Modes
The DLRO10HD measures low resistance values in applications ranging from railways and aircraft to resistance of components in industry.

Any metallic joint can be measured but users must be aware of measurement limitations depending on application. For example, if a cable manufacturer plans to make resistive measurements on a thin wire, a low test current should be selected to prevent heating the wire thereby changing its resistance.

Measurements on electric motors and generators will be inductive and require the user to understand the inductive mode and charging process before a correct result is achieved. The DLRO10HD is well suited to measure thick conductors, bonds and quality of welding because of its 10A range for resistance values up to 250mΩ.

Electromagnetic noise induced into the leads can interfere with a reading. A noise symbol alerts the user and prevents a measurement when the instrument detects noise above its threshold.

When dissimilar metals are joined a thermocouple effect is created. Users should select a bidirectional mode to ensure cancellation of this effect. The instrument measures with current flowing in both directions and averages the result.

Normal mode is initiated by pressing the 'Test' button after connecting the test leads to the unit under test. Continuity of all four connections is checked. Current is applied in both forward and reverse direction following which measurement is displayed.

Automatic mode is started as soon as the probes make contact. Forward and reverse current measurements are made and the average value is displayed. This mode is ideal when working with supplied DH4 handspikes. Each time the probes are removed and reconnected to the load a new test will be performed without the need to press the test button.

Continuous mode allows repeated measurements to be made on the same sample. Simply connect the test leads and press the test button. The measurement is updated every three seconds until the circuit is broken.

Inductive mode is selected when measuring resistance on, for example, motors and generators. When measuring inductive loads it is necessary to wait for the voltage to stabilize as the inductive element is charged. Test leads are firmly connected to the device under test under test and the 'Test' button pressed. The instrument will pass the selected current through the sample continuously in one direction only and take repetitive readings that will gradually decrease to the true value as the voltage stabilizes. The operator decides when the result is stable and presses the 'Test' button to terminate the test.