EMAS RDH1A digital frequency meter with a 30 to 70 Hz measuring range, 100 to 250 V AC measurement interval, three-digit display and 1CO relay output.
£93.94
The EMAS RDH1A is a compact digital frequency meter and monitoring relay designed for measuring AC supply frequency in industrial electrical panels, machinery and power distribution systems. Part of the EMAS RD series, it combines clear digital frequency indication with an integrated changeover relay output for monitoring, alarm and control applications.
The RDH1A measures AC voltage and frequency across a range of 100 to 250 V AC and 30 to 70 Hz. Its three-digit seven-segment display provides a clear indication of the measured frequency, helping engineers identify abnormal supply conditions that could affect motors, generators and sensitive electrical equipment.
Operating from a nominal 230 V AC, 50 Hz supply, the device includes a 1CO changeover relay output with a resistive contact current rating of 5 A. Its compact eight-pin format, fast and quiet switching, long operating life and finger-safe design make it well suited to industrial control-panel applications.
Electrical frequency meters monitor the frequency of an AC supply and help operators identify conditions that fall outside the required operating range. Excessively high or low frequency can affect motor speed, generator performance, timing systems and other frequency-sensitive electrical equipment.
The EMAS RDH1A provides continuous digital indication across its 30 to 70 Hz range. Its integrated relay output can be connected to an alarm, contactor or control circuit, allowing the meter to form part of a wider electrical monitoring and protection system.
| Current | 1 A |
|---|---|
| Voltage | 230 V |
| Manufacturer | EMAS |
| Series | RD Series |
| Model | RDH1A |
| Product type | Digital frequency meter panel meter |
| Control type | Digital |
| Measurement type | AC frequency and voltage |
| Frequency measuring range | 30 to 70 Hz |
| Voltage measuring range | 100 to 250 V AC |
| Operational voltage | 230 V AC |
| Permitted voltage range | 0.85 to 1.1 × Ue |
| Nominal operational frequency | 50 Hz |
| Display type | Seven-segment display |
| Number of display digits | 3 |
| Connection type | 8-pin |
| Contact configuration | 1CO changeover contact |
| Resistive contact current | 5 A |
| Relay output rating | 10 A at 250 V AC |
| Maximum contact power | 1500 VA |
| Contact material | AgNi |
| Maximum switching frequency | 6,000 operations per hour |
| Mechanical endurance | Minimum 10,000,000 operations |
| Electrical endurance | Minimum 100,000 operations |
| Operating temperature | -5 to +55 °C |
| Protection rating | IP20 |
It is used to measure and monitor the frequency of an AC electrical supply in industrial panels, generators, machinery and distribution systems.
The EMAS RDH1A measures AC supply frequencies between 30 and 70 Hz.
The meter has a measuring interval of 100 to 250 V AC and operates from a nominal 230 V AC supply.
Yes. It includes a 1CO changeover relay output for connection to alarms, contactors or control circuits.
The frequency meter uses a clear three-digit seven-segment digital display.
EMAS digital panel meters are used by panel builders, machinery manufacturers and electrical engineers to provide clear measurement, dependable monitoring and reliable relay control within industrial electrical systems.
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LED Controls is a specialist distributor of factory automation and industrial controls, supplying OEMs, machine builders, panel builders and end users throughout the UK and worldwide. As a trusted UK distributor for many of the world’s leading automation manufacturers, we provide industrial control products, technical expertise and bespoke automation solutions backed by outstanding customer service.
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...