5
RMO25W
Functionality
4 Functionality
The RMO25W generates a filtered (true) DC current.
RMO25W test set can measure the winding resistance of any transformer; small
or very large, single or three phase, star, delta or zig-zag connected. There are
two independent measuring channels which can used to simultaneously measure
resistance of up to two windings at the same time.
Choose measuring current so that for the expected resistance you have
maximum value of it
(refer to section 6.5 on page 12).
Note:
Before the test, measuring channels should be defined.
If one measuring channel is chosen, (Ch:1), then the left channel is
active.
At the start of the test a check of cables connection is done. In case of
disconnection, an alarm is activated, and the error message is shown
on the display.
RMO25W injects current with a voltage as high as 50 V at start. This ensures that
the test is as short as possible, and that the desired test current is reached as soon
as possible. The DC current is selectable up to 25 A. Testing current of 25A could
last up to 90 seconds, testing current of 10A could last up to 300 seconds, while
current of 5 A, and less, could last up to 900 seconds maximum. The test result is
displayed as R=U/I.
The test is started pressing the
Ω
button. When the current is stabilize, RMO25W
measures the resistance of the test object. During the test, a new result is shown
on the display approximately each second.
Each push on the
Ω
button results with input of the resistance current value into
the internal memory of RMO25W, and memory location changes to the next one.
Test could be accomplished two ways:
- Pushing
to
STOP
button,
- Automatically after to expire of selected time.
In both cases upon accomplished test measured value of the resistance is recorded
to pre-selected internal memory location.
Minimal time of measurement is 60 seconds.
By pushing
STOP
button test could be performed at any time. When the
STOP
button is pushed, the last measured result will remain saved in the internal
memory.
Upon expiry of the selected test lasting time, the last result remains saved at
selected memory location.
