Overload Relays & Power Controllers for Food Processing & Cold Chain

When Your Electricity Bill Is Bigger Than Your Refrigeration Bill

Here is a situation every panel-builder who has worked in food processing or cold chain infrastructure will recognise. The distribution company's maximum demand meter ticks past the sanctioned load — not because the compressors drew more current, but because three ancillary loads (a conveyor drive, a packaging heater bank and an exhaust fan array) happened to start simultaneously during a peak-tariff window. The result: a demand penalty on the monthly bill that dwarfs the cost of the energy itself. Nobody tripped. No contactor welded. No fuse blew. Yet the facility paid a premium for an overload that lasted less than fifteen minutes.

This is the load-management problem in food processing and cold chain, and it is structural — not accidental. This article explains why it happens, what the correct panel-level solution looks like, and how three Novatek Electro devices — the OM-310, the OM-163 and the RMT-101 — provide the contactor-driving and overload-protection functions that make a practical demand-side management (DSM) scheme work.

Why the Problem Is Structural, Not Accidental

The Nature of Food-Processing and Cold-Chain Loads

Food processing and cold chain infrastructure share a common electrical characteristic: coincident load diversity is low during critical operating windows. Refrigeration compressors cycle on thermal demand. Conveyor drives start on production schedule. Defrost heater banks on refrigerated display and storage equipment fire on timer. Wash-down pumps and CIP circuits activate on shift changeover. These events are individually predictable but collectively unsynchronised — and when they coincide, the aggregate kVA demand spike is sharp, short and expensive.

Under a two-part tariff structure — fixed charges on sanctioned maximum demand plus energy charges on kWh consumed — even a brief demand exceedance in a billing cycle can ratchet the recorded maximum demand upward, attracting penalty charges that persist for months under ratchet-clause provisions common in commercial and industrial tariff schedules. The electrical engineering cause is straightforward: no panel-level intelligence exists to shed non-critical loads when the aggregate current approaches the demand threshold.

Power Factor Drift Compounds the Problem

Induction-motor-heavy installations — compressor racks, conveyor drives, ventilation fans — present lagging power factors that inflate kVA demand even when active-power (kW) consumption is within sanctioned limits. Without real-time power monitoring at the panel, operators are blind to reactive power drift until the utility bill arrives. By then, the billing cycle is closed.

The Panel-Level Solution: Demand Control with Overload Protection

A practical DSM scheme at the MCC or sub-distribution panel level requires three functions running simultaneously:

• Real-time monitoring of current, voltage, active power, reactive power and apparent power (kVA).
• Demand control — contactor-driven load shedding of non-critical circuits when aggregate demand approaches a set threshold.
• Overload and earth-fault protection on individual circuits to prevent equipment damage independently of the demand-control logic.

Novatek Electro's OM-310, OM-163 and RMT-101 are designed to deliver exactly these three functions — at the panel level, without SCADA integration overhead, at a combined cost that is recoverable within a single billing cycle in a medium-sized facility.

OM-310 — Three-Phase Demand Controller and Overcurrent-Earth Fault Relay

The OM-310 is a numeric, multi-functional protection and demand-control relay covering three-phase and four-pole installations across a current range of 5 A to 800 A (corresponding to 2.5 kW to 450 kW motor loads) at 380–415 V AC. It combines overcurrent protection, earth-leakage protection, power monitoring and demand control in a single DIN-rail device with a dual LED display.

What the OM-310 Does in a Demand-Control Scheme

• Demand threshold monitoring: The relay continuously monitors three-phase current and computes apparent load. When aggregate demand approaches the user-set threshold, the OM-310 drives an output contact to shed a pre-assigned non-critical contactor — exhaust fans, secondary conveyor segments, non-process lighting circuits or secondary refrigeration fans are typical candidates in food-processing panels.
• Overcurrent protection: Independent of the demand-control function, the OM-310 provides phase overcurrent protection across its full 5–800 A range, tripping contactors on sustained overcurrent conditions that indicate motor overloads or feeder faults.
• Earth-fault (earth-leakage) protection: In hygiene-critical environments where wash-down routines are frequent, earth-fault currents are a real hazard. The OM-310 monitors earth leakage and trips on exceedance, protecting both equipment and personnel.
• Power monitoring via dual LED display: Operators can read load parameters without handheld instruments, enabling shift-level awareness of demand trends.

Price: Rs. 15,687 per piece (ex-GST, GST @ 18% extra)

OM-163 — Single-Phase Power Controller, Voltage Monitor and Energy Meter

Where single-phase sub-circuits carry ancillary loads — packaging-line heater banks, single-phase display-case defrost elements, single-phase conveyor controls or laboratory refrigeration units — the OM-163 provides power limiting, voltage monitoring and energy metering in a compact 2-pole device rated at 63 A at 250 V AC, operable across a supply range of 130–300 V.

Measured and Controlled Parameters

The OM-163 is powered by the circuit that feeds the load — no separate auxiliary supply is required. Its 3-digit display shows measured values and relay status via LED indicators, giving panel-builders a low-cost metering point at every sub-circuit without wiring a separate energy meter. The power-limiting function drives a relay output to disconnect or throttle a load when power consumption exceeds the set threshold — exactly the behaviour required for sub-circuit load shedding in a single-phase demand-control architecture.

Price: Rs. 3,500 per piece (ex-GST, GST @ 18% extra)

RMT-101 — Overcurrent Relay for Load Rejection on Individual Circuits

The RMT-101 is a dedicated current overload and overcurrent relay designed for load rejection when current exceeds a user-set value between 0 and 100 A (fully settable). Its electrical specifications reflect industrial-grade construction: nominal insulation voltage of 450 V, rated impulse withstand voltage of 2.5 kV, protection degree IP40 (device) and IP10 (terminal block), and pollution-degree II / overvoltage-category II ratings consistent with panel installation in process environments.

Role in a Demand-Management Panel

In a tiered load-shedding scheme, the OM-310 handles aggregate three-phase demand at the incomer level while RMT-101 units provide independent overcurrent-trip authority on individual branch circuits. This layered architecture ensures that a demand-shed event (initiated by the OM-310 or a PLC demand-management controller) is supported at the branch level by discrete overload protection — so that a single faulted load cannot prevent the demand-shed contactor from dropping correctly.

Price: Rs. 5,475 per piece (ex-GST, GST @ 18% extra)

Quick Selection Guide

Typical Application Categories in Food Processing and Cold Chain

• Refrigerated warehousing and cold stores: Demand control on compressor-rack MCC panels, with load shedding of secondary evaporator fans and lighting during peak-tariff windows.
• Food processing plants (meat, dairy, bakery, beverage): Tiered load shedding across conveyor drives, heater banks and compressed-air systems to stay within sanctioned maximum demand.
• Blast freezing and IQF tunnels: Overcurrent protection on high-inertia drive circuits where starting current transients can trigger demand spikes.
• Packaged food manufacturing: Single-phase power limiting on packaging-line heater elements using OM-163 to prevent process heaters from contributing to demand peaks.
• Retail refrigeration and supermarket display: Per-circuit overcurrent and load-rejection control on display-case circuits using RMT-101.
• Cold-chain logistics hubs and distribution centres: MCC-level demand management across multiple refrigerated docking zones, using OM-310 for incomer monitoring and RMT-101 for zone-level protection.
• Agri-processing and grain storage: Demand control during peak harvest season when dryer loads, conveyor drives and refrigeration operate simultaneously.

Why Novatek Electro?

• ISO 9001:2015 certified — quality management systems audited and certified, ensuring consistent product performance batch to batch.
• CE certified — products meet European electromagnetic compatibility and low-voltage directive requirements, confirming design rigour applicable to Indian industrial environments.
• Made in India, designed for Indian grid conditions — products rated for the voltage and frequency tolerances characteristic of the Indian distribution network.
• 30+ years of manufacturing experience in electrical protection devices, with a product range spanning voltage monitoring, motor protection, power control and demand management.
• After-sales support through authorised distributor network — technical support, replacement and documentation available through intelli-electro.com and the Novatek Electro sales team.

Frequently Asked Questions