After-Sales Service; Q&A - Mitsubishi EMU4-BM1-MB User Manual

9.2 After-sales service

If you have any questions or the product is broken down, contact our sales representative near you. (For details, refer to the
end of this manual.)
･ Gratis warranty is effective until the earlier of 1 year after the date of your purchase or 18 months after manufacturing.
･ The gratis warranty shall apply if the product fails even though it is being used properly in the conditions, with the methods and
under the environments in accordance with the terms and precautions described in the catalogs, the instruction manual,
caution label on the product, etc.
･ Repair shall be charged for the following cases even during the gratis warranty period.
- Failures occurring due to your improper storage or handling, carelessness or fault.
- Failures due to faulty workmanship
- Failures due to faults in use and undue modification
- Failures due to accidental force such as a fire, abnormal voltage, etc. and force majeure such as an earthquake, wind,
flood, etc.
- Failures due to matters unpredictable based on the level of science technology at the time of product.
Our company shall not be liable to compensate for any loss arising from events not attributable to our company, opportunity
･
loss and lost earning of the customer due to failure of the product, and loss, secondary loss, accident compensation,
damage to other products besides our products and other operations caused by a special reason regardless of our
company's predictability
9.3 Q&A
■General
Q
To what degree is the unit durable against overvoltage and over current?
Durability is as follows:
Momentary*: Up to 20 times as high as rated current and 2 times as high as rated voltage.
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*Momentary means: Energizing 9 times for 0.5 seconds at 1-minute intervals, and then 1 time for 5 seconds.
Continuous: Up to 1.1 times as high as rated voltage and rated current.
Q
Can the unit be used as an electric energy meter?
A
This unit cannot be used for deal and proof of electric energy measurement stipulated in the measurement law.
Q
Are errors in wiring verifiable easily?
They are verifiable by the indication for discrimination support function for improper connection in instruction manual (detail) of display
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unit.
Q
Is it OK to open the secondary terminals of the current sensor?
The secondary side of the models EMU2-CT5, EMU2-CT5-4W, EMU-CT50, EMU-CT100, EMU-CT250, EMU-CT5-A, EMU-CT50-A,
EMU-CT100-A, EMU-CT250-A, EMU-CT400-A, and EMU-CT600A is equipped with the protective circuit against opening of secondary
terminals. Opening them during the wiring work causes no problems. However, for safety, please do not continuously energize the module
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with the terminals open.
The secondary side of the models EMU-CT400 and EMU-CT600 is equipped with the protective circuit against opening of secondary
terminals. However, during the wiring work, be sure to turn the secondary side short-circuit switch to short. After completion of work, be
sure to turn the secondary short-circuit switch to open. Note that failing to turn the switch open results in an inaccurate measurement.
Q
If a load such as welding equipment exists, a current flows only for a short period (e.g. 2 cycles). Is measurement possible?
The electrical amount such as current, voltage, electric power, power factor, frequency, harmonic voltage and harmonic current is
measured in a cycle of 100 ms period. So it is impossible to measure the current accurately for a short period.
A
The amount of electricity and reactive power amount are measured separately from the momentary data described above, using a
sampling period of 4kHz continuously without intermittence. Therefore, it is possible to measure the load for a short period.
Q
Obtained values may be different from other measuring instruments. Why is it so?
There are various possible causes. Check the following first, please:
(1) Check for wiring errors.(Especially, polarity of current sensor and connection of voltage circuit)
(2) Check for the settings. (phase wires, primary voltage ,primary current and sensor type)
(3) On the split-type current sensor, check for the poor engagement or separation of fitting surfaces.
(4) On the split-type current sensor, check for pinching of foreign object between fitting surfaces.
(5) Check for the short circuit on the secondary side of the current transformer (CT).
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(6) Current sensor connectable to the unit is the dedicated current sensor only. Check that the proper current sensor is connected or
not.
(7) Check that the measuring instrument used for comparison indicates a correct RMS value.
This unit indicates an RMS value. If the measuring instrument used for comparison measures an average value
instead of RMS value, distortion caused by harmonic etc. in the current of the circuit to be measured causes a
significant difference of values.
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