Milesight CT101: run hours and current from a clamp

Why current is the most useful signal you can add

A motor that runs draws current; a motor that stops does not. That simple fact gives maintenance two things it rarely has: the real number of hours a machine worked, and an early sign when its behaviour changes. A pump that draws more current for the same job is often wearing; a fan that draws less may have lost its belt; a compressor that never stops points to a leak.

Run hours matter because most manufacturers’ service intervals are written in hours. Without a counter, maintenance falls back on calendar plans that over-maintain the machines that rarely run and under-maintain the ones that never stop. Counting hours from the current fixes both.

• Real run hours for hour-based service intervals
• Early warning when the current drifts at the same load
• Confirmation that a machine is running when it should be

How the readings reach FreeMaint

The CT101 sends its readings over LoRaWAN to a gateway. Your network server — The Things Stack (The Things Network or The Things Industries), ChirpStack, or the server built into a Milesight UG65 or UG56 gateway — forwards each message to FreeMaint over HTTPS. FreeMaint gives you the URL and the header to paste when you create the connection.

Do not set a payload codec on a Milesight gateway: FreeMaint needs the full message to decode the CT101 itself. The sensor is recognised automatically and its channels appear on the first message. FreeMaint keeps its radio signal and its last message; once you confirm the sensor, it is flagged as late, then offline, against the interval you expect.

One thing to know about a self-powered clamp

The CT101 takes its power from the cable it measures. When the current falls below about 1.4 A, it stops reporting. A gap in its data can therefore simply mean that the machine is off. Keep this in mind when you create a no-data rule: on a machine that stops every night, a no-data alert would fire every night. Use it on equipment that should run continuously, and use run hours and current thresholds everywhere else. The same goes for the sensor’s connection state: on a machine that stops every night, the CT101 shows as late, then offline, until the machine runs again.

From run hours to a preventive work order

Open the current channel and choose Calculate run hours. Set the current above which the machine counts as running, and FreeMaint creates a calculated channel that adds up the running time. Link it to the asset’s run-hours meter: FreeMaint writes a reading every 60 minutes by default, and the meter’s preventive plans and triggers work exactly as with manual readings.

Connecting devices is part of the Business plan, at $99 per month per company, flat, with 100 active channels. Meter-based preventive maintenance itself is part of the Starter plan. FreeMaint sells no hardware: the CT101 is bought from Milesight or its distributors, and it carries the Compatible badge, validated against Milesight’s documentation.