Measure the machine or the entire cell? Defining the energy measurement boundary

An injection moulding machine operates alongside auxiliary equipment needed for production: dryers, temperature control units, robots, cooling equipment and other loads. Their electrical connections determine which loads can be measured separately.

Measuring one supply: what the data show

When a meter monitors the injection moulding machine’s main incoming supply, the power curves and accumulated energy readings represent that connection. They show trends, peaks and energy consumption over a defined period. Auxiliary loads contribute to that reading only if they are supplied through the measured circuit.

Measuring several supplies: what changes

Instrumenting several independent electrical connections in the cell makes it possible to examine the contribution of each selected load. This breakdown helps establish whether the largest energy consumption came from the injection moulding machine, the dryer or the mould temperature control unit, depending on which equipment is connected to the monitoring system.

Dryer

12.4 kW

Power · example

Example

Machine

28.6 kW

Power · example

Example

Mould temp.

8.7 kW

Power · example

Example

Auxiliaries

4.1 kW

Power · example

Example

Electrical power demand of the cell

53.8 kW
Power

Injection-moulding machine · 53%

Dryer · 23%

Mould temperature controller · 16%

Other auxiliary equipment · 8%

Accumulated energy (shift)352.1 kWh

Specific energy consumption0.42 kWh/kg

Illustrative values for equipment power, accumulated energy and specific energy consumption.

Define the cell’s electrical boundary

A cell may include loads shared with other machines, integrated circuits and distribution boards supplying a mixture of equipment. Before preparing a quotation, identify the equipment, measurement points, voltage, number of phases, available connections and conditions for safe access. The installation design is agreed with authorised technical personnel.

What to record for a sound comparison

Comparing kWh between two shifts requires operating context to assess process efficiency. Record whether the equipment was producing, heating up, waiting or undergoing a mould change, and explicitly maintain the same electrical measurement boundary. Calculating kWh/kg or kWh/part requires reliable records of the mass or number of parts produced, together with an agreed denominator: total production or conforming output.

The first step towards a quotation

KERN Energy allows the measurement scope to be defined around your needs: explore Machine and Cell or describe your cell to prepare a technical configuration.

To break down the consumption of several electrical supplies within a cell, see KERN IoP | ENERGY: Cell. To investigate loads that remain active outside production, see standby energy in an injection moulding cell.