Haberler

When purchasing a large hydraulic baler, scrap shear, gantry shear or metal recycling machine, selecting the correct capacity and model is only part of the project. One question can determine whether the equipment can actually be commissioned successfully: can the existing factory power system support it?

In scrap yards, steel plants, foundries and recycling facilities, buyers naturally focus first on production requirements:

“How many tons per hour can the machine process?”

“What cutting or compression force do we need?”

“What is the installed motor power?”

However, before the equipment specification is finalized, another question deserves equal attention:

How much electrical capacity is actually available at the installation site?

If this is discovered only after the machine has been manufactured—or worse, after it arrives at the factory—the buyer may face transformer upgrades, larger cables, switchgear modifications and commissioning delays.

Why Knowing “400V, 50Hz” Is Not Enough

A common electrical specification provided during an international equipment inquiry is:

400V / 50Hz / 3 Phase

This information is necessary, but for machinery using tens or hundreds of kilowatts of installed motor power, it is not enough to determine whether the factory can operate the equipment.

Buyers and suppliers should distinguish between several electrical parameters.

Voltage (V) determines the electrical rating required for motors and electrical components.

Frequency (Hz)—commonly 50Hz or 60Hz—affects motor and electrical system selection.

Phase is normally three-phase for heavy industrial hydraulic equipment.

But another question is frequently overlooked:

What is the maximum incoming current available, and how much spare transformer capacity does the factory actually have?

Two factories may both have 400V/50Hz/3-phase electricity while having completely different abilities to operate the same machine.

One may have substantial spare transformer capacity. At another facility, existing production lines, compressors, cranes and other machinery may already consume most of the available power.

Therefore:

Correct voltage does not automatically mean sufficient power capacity.

The Hidden Problem: Starting a Large Motor

Large hydraulic recycling equipment commonly uses high-power three-phase induction motors to drive hydraulic pumps.

A motor rated at 37kW, 55kW or 75kW describes its rated operating condition. It does not tell the full story of what happens during startup.

Large motors can draw several times their rated current during starting. Schneider Electric notes that large motors started directly online can draw approximately five to seven times rated current, potentially causing significant voltage drops when connected to a relatively weak electrical network.

This explains a situation that can otherwise be confusing to buyers:

The factory may have enough power to run the machine after startup, but still struggle to start it.

Possible symptoms include nuisance breaker trips, unsuccessful motor acceleration, voltage dips, disturbances to other equipment, protection trips and insufficient starting torque.

Cable design matters as well. Long motor cables introduce voltage drop, and excessive voltage drop can affect both current consumption and available motor torque.

A Common Mistake: “The Machine Has 110kW of Motors, So We Only Need 110kW”

Electrical sizing should not be approached this way.

Consider a recycling machine equipped with two 55kW motors, giving 110kW of total installed motor power.

Simply calculating:

55kW × 2 = 110kW

does not prove that the existing electrical infrastructure is sufficient.

The engineering assessment should also consider whether the motors start simultaneously or sequentially, the starting method, rated motor current, permitted starting current, existing loads on the transformer, transformer spare capacity, cable length and the voltage drop that the facility can tolerate.

In other words, the electrical system must be evaluated as a system—not simply by reading the kW figure on the quotation.

What If the Factory Does Not Have Enough Electrical Capacity?

Insufficient capacity does not necessarily mean that the project must be cancelled.

The important point is to identify the limitation before manufacturing begins.

Option 1: Review the Motor Starting Method

Depending on the machine and load characteristics, star-delta starting, soft starters or variable frequency drives may be considered.

A soft starter can reduce electrical stress during acceleration, while a VFD controls both voltage and frequency to provide more controlled acceleration.

Schneider Electric's analysis of large-motor starting illustrates that DOL, reduced-voltage soft starting and VFD starting can produce substantially different starting currents and corresponding voltage drops.

However, there is an important limitation:

A soft starter or VFD cannot create electrical capacity that the factory does not have.

It may reduce startup demand, but if the available transformer capacity is insufficient even during normal machine operation, changing the starting method alone will not solve the fundamental problem.

Option 2: Start Large Motors Sequentially

For machines equipped with multiple main motors, the manufacturer may evaluate whether sequential starting is technically possible:

Motor 1 starts and stabilizes → Motor 2 starts

This can prevent multiple starting-current peaks from occurring at exactly the same moment.

However, this must be evaluated according to the hydraulic system and operating logic. Buyers should not modify the starting sequence independently after installation.

Option 3: Upgrade the Transformer or Distribution System

If normal operating demand is already close to or above the facility's available capacity, the practical solution may involve increasing transformer capacity, installing a dedicated transformer, or upgrading the incoming feeder, switchgear or cables.

Such work should normally involve a qualified local electrical engineer because utility conditions, protection requirements, short-circuit levels and local electrical regulations vary between projects.

Option 4: Redesign the Equipment Around the Available Supply

When upgrading the factory grid is prohibitively expensive, the buyer can provide the maximum available current to the machine manufacturer and investigate an alternative configuration.

Possible changes may include a different motor combination, optimized starting sequence, alternative starting method, revised production target or distribution of loads across separate electrical supplies.

But buyers should be cautious about one apparently simple solution:

Reducing motor power just to meet the incoming-current limit while expecting exactly the same production performance.

In a hydraulic machine, motor power, pump flow, hydraulic pressure, cycle time and production capacity are interconnected. Lowering available drive power may reduce operating speed or prevent the equipment from reaching its original design performance.

Electrical Information Buyers Should Provide Before Ordering

A useful pre-purchase electrical checklist includes:

If the available incoming current is unknown, the buyer can ask a local electrician to check the main breaker, transformer nameplate and existing facility loads, then share the relevant specifications or photos with the equipment supplier.

Why This Discussion Should Happen Before Manufacturing

For heavy industrial machinery, adapting the electrical system is not simply a matter of “changing the plug.”

Different voltage, frequency and site-power conditions can affect the motors, electrical cabinet, breakers, contactors, soft starters or VFDs, cable sizing, protection strategy and control design.

The later a mismatch is discovered, the more expensive it can become.

Finding the problem during technical evaluation allows the buyer to compare the cost of upgrading the facility's electrical infrastructure against the cost and performance implications of modifying the machine configuration.

Finding the same problem after the equipment arrives can mean installation delays, additional engineering work and disruption to the buyer's production schedule.

A Practical Recommendation for Buyers

Before ordering a scrap metal baler, hydraulic shear, gantry shear, briquetting press or large metal recycling machine, do not stop at asking:

“How many kilowatts does this machine need?”

Ask the more useful question:

“Can this machine start safely and operate continuously with the electrical capacity currently available at our factory?”

Before signing the order, the machine supplier and the buyer's local electrical engineer should ideally verify the supply voltage, frequency, rated operating current, starting method, expected starting current, transformer capacity and existing facility loads.

For a large industrial project, the least expensive electrical problem is the one discovered before the machine is built.