Taiwan Meters Ammeters & Current Transformers

Taiwan Meters ammeters and current transformers for industrial control panels

For many industrial panels, a clear local indication of electrical current is still useful for commissioning, routine inspection and fault-finding. Taiwan Meters ammeters and current transformers provide two established ways of achieving that measurement: direct analogue indication for lower-current circuits and current-transformer measurement where the primary current is higher.

Charter Controls carries a focused selection of Taiwan Meters analogue AC ammeters together with MFO measuring current transformers. The important engineering point is to select them according to the actual measurement architecture. A direct-reading ammeter and a 5 A current-transformer measuring circuit are not interchangeable arrangements.

What do Taiwan Meters ammeters and current transformers do?

An analogue ammeter gives an engineer an immediate visual indication of the current flowing in the monitored circuit. This can be useful on motor control panels, switchboards, machinery and other electrical equipment where a local current indication is required at the enclosure or operator panel.

A measuring current transformer performs a different job. It reproduces the primary circuit current at a lower, proportional secondary current that can be handled by compatible measuring equipment. All of the MFO current transformers covered here have a nominal 5 A secondary.

For example, a 750/5 A CT is selected for a measuring system designed around a 750 A nominal primary and a 5 A secondary instrument circuit. The connected meter or measuring device must itself be suitable for a 5 A CT input and scaled for the intended primary-current range.

Verified Taiwan Meters analogue AC ammeters

The Charter Controls range includes compact 48 × 48 mm instruments and larger 96 × 96 mm instruments. They are panel-mounted AC ammeters with a 90° scale.

When to choose a direct-reading analogue ammeter

A direct-reading unit is appropriate where the intended circuit and measurement arrangement fall within the meter's specified direct current range. It is a straightforward option for projects that require a dedicated local analogue indication rather than current measurement being provided only through a multifunction meter, HMI or control system.

Panel format is also a practical consideration. The 48 × 48 mm instruments suit applications where front-panel space is restricted, while the 96 × 96 mm format provides a larger instrument face where the panel layout has sufficient room.

Taiwan Meters MFO current transformers available from Charter Controls

The MFO range covered here consists of Class 1 measuring current transformers with a nominal 5 A secondary. The primary ratings extend from 50 A to 2500 A, with the listed VA burden increasing across the range.

How to select a Taiwan Meters ammeter or current transformer

1. Decide whether the current will be measured directly or through a CT

Start with the electrical design rather than the physical meter size. The BE48 and BE96 ammeters above are direct-reading ammeters. The MFO products are measuring current transformers with 5 A secondaries.

Do not assume that a direct-reading BE ammeter can simply be connected to the secondary of an MFO transformer. A CT-based measuring circuit requires an instrument specifically intended for the corresponding CT secondary and correctly scaled to represent the primary current.

2. Select the correct primary-to-secondary CT ratio

The CT ratio must suit the current being measured and the instrument connected to its secondary. The verified MFO options include 50/5 A, 75/5 A, 100/5 A, 200/5 A, 400/5 A, 750/5 A, 1500/5 A and 2500/5 A ratios.

A 200/5 A CT, for example, is intended to provide the standard 5 A secondary value at its 200 A rated primary condition. The corresponding instrument or monitoring input must be selected and configured for that measurement ratio.

3. Check the CT burden

The secondary circuit imposes a burden on the current transformer. The verified MFO range includes burdens of 2.5 VA, 5 VA, 10 VA and 15 VA. When specifying a CT, check the complete measuring circuit rather than considering the transformer in isolation. The connected instrument and secondary wiring both form part of the circuit that must remain within the specified design limits.

4. Check the accuracy requirement

The MFO models covered above are listed as Class 1 current transformers. Confirm that this accuracy class is appropriate for the project specification and intended measuring duty before selecting the transformer.

5. Check the physical installation

For an analogue ammeter, verify the available panel space and the required front format before ordering. The range covered here includes 48 × 48 mm and 96 × 96 mm Taiwan Meters ammeters.

For an MFO current transformer, check the installation arrangement against the conductor or busbar and the available internal panel space. The MFO model designation changes across the higher primary-current ratings, so physical suitability should be checked from the relevant product drawing or datasheet rather than inferred from the ratio alone.

Installation and panel wiring considerations

Analogue ammeters and measuring CTs should be treated as part of the panel's measurement circuit, with conductor sizing, protection, isolation, terminal identification and wiring routes established by the electrical design.

Current-transformer secondary circuits require particular care. An energised measuring CT secondary should not be left open circuit. Isolation, shorting and maintenance procedures should follow the approved electrical design and safe working procedure for the installation.

For replacement work, confirm the existing instrument type, current range, panel format and wiring arrangement before removing the old meter. A matching front size alone does not establish electrical compatibility.

Where analogue current measurement still makes sense

Taiwan Meters ammeters and MFO current transformers are suited to industrial panels where engineers need straightforward local current indication or a conventional CT-based measurement circuit. Typical projects can include machinery panels, motor control equipment, distribution panels, switchboards, packaged equipment and refurbishment work where the project specification retains analogue instrumentation.

They can also be useful where a panel builder needs a dedicated current indication separate from the control system. The instrument remains a measurement component rather than a substitute for overload protection, motor protection or process-load monitoring.

Direct ammeter or current transformer: selection summary

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