Motor kW and Your Site Supply

The motor rating on a specification sheet is a capability figure; the supply at your site is a constraint, and the two have to meet before the build rather than on delivery day. This article is the motor-and-supply conversation at the entry class — what the kW options mean, what your electrician needs to confirm, and why the configuration is fixed at quotation. The reference machine is the Q91-200, whose published motor options span 22 to 2×22 kW.

What the Options Mean

The Q91-200 publishes four motor configurations: 22, 27, 30, or 2×22 kW. They are not an upsell ladder — they are answers to different site situations:

• The lower kW configurations suit generator- or diesel-powered sites, where the supply is limited and a smaller motor starts cleanly on what is available.
• The higher configurations suit grid-connected yards with throughput ambitions, where the supply can start a larger motor and the daily tonnage justifies it.
• The twin-motor option splits the load, which suits supplies that can carry the total power but struggle with the starting demand of a single large motor.

What the choice does not change is the cutting capability — the force rating is the force rating. What it changes is whether the machine starts cleanly on your supply and how it behaves across a shift, and both of those are site facts rather than machine facts.

What Your Electrician Confirms

Three numbers decide the configuration, and all three come from your electrician before the build:

Available voltage and frequency. The Q91-200 is configurable for 380V, 400V, 415V or 230V at 50Hz or 60Hz — your supply picks one, and the machine is built for it rather than adapted afterwards.

Spare capacity in kilowatts. Not the supply’s total capacity — the capacity available after the yard’s existing load. A motor that fits the supply on paper and not on the yard’s peak day is a problem discovered in production.

The starting method. How the motor starts — direct, soft, or through a starter matched to your transformer — and whether the supply can deliver the starting demand. This is the row that most often decides between a single larger motor and the twin-motor option, and it is confirmed in writing before the build.

Send those three with your inquiry and the electrical scope comes back confirmed in writing before the machine is built. The alternative — discovering the constraint on delivery day — is the most expensive version of this conversation.

Why the Configuration Is Fixed at Quotation

Motor rating, voltage, frequency and power source are build decisions, not field adjustments. A machine built for 400 V 50 Hz is not a machine that runs on 415 V 60 Hz with an adaptation — it is a different build. The same applies to the power source: grid electric, generator and diesel packages are different configurations fixed before the machine is built, and the quotation is where the choice is made against your site.

This is also why the site conversation happens at quotation rather than after the order. The foundation, the supply and the motor are one specification, and the yard that has all three confirmed in writing before the build commissions in week one — the yard that discovers them at the port spends the first month rebuilding the connection.

The Supply Across the Range

The same logic scales up the range, and the stakes rise with the class. The 315 and 400 classes commonly exceed what a small yard’s existing supply can start cleanly, which is why the starting-method conversation matters more at each step up. At mill scale the supply conversation is a project rather than a phone call — and the three-shift economics guide covers the energy baseline the supply has to carry.

The Supply Conversation

The supply conversation has three numbers and one document, and all four come from your electrician before the build. The numbers: available voltage and frequency, spare capacity in kilowatts after the yard’s existing load, and the starting demand your supply can deliver. The document: the electrical scope, confirmed in writing before the machine is built — motor package, starting method, protection arrangement, and what your electrician needs to verify the installation.

The conversation is cheap at quotation and expensive at delivery. A machine built for the wrong voltage is not adapted — it is rebuilt — and a starting method your supply cannot deliver is discovered on the day the production plan was waiting. Send the three numbers with your inquiry and the scope comes back in writing before the build.

The Configuration, Fixed

Motor rating, voltage, frequency and power source are fixed at quotation because they are build decisions rather than field adjustments. The Q91-200’s published options — 22, 27, 30 or 2×22 kW, across 380/400/415/230V at 50 or 60 Hz, on grid, generator or diesel — are answers to different site situations, and the quotation picks one against your facts.

The same logic scales up the range, and the stakes rise with the class. The starting-methods guide covers the mill-scale version of this conversation, where the supply question becomes a project — and the supply guide covers the entry-class arithmetic.

The Supply, Priced

The supply conversation prices in two currencies, and both are visible before the build. The equipment currency: motor package, starting method, protection arrangement — each a line in the electrical scope. The capacity currency: the spare kilowatts the machine needs after the yard’s existing load, and the upgrade cost if the supply cannot deliver it. A yard that discovers the capacity gap on delivery day buys the upgrade at emergency prices; a yard that confirms it at quotation buys it at planned prices, or configures the machine to fit the supply it has.

This is why the three numbers — voltage, frequency, spare kilowatts — come from your electrician before the build rather than after the order. The starting-methods guide covers the mill-scale version, where the capacity question becomes a project, and the configuration that comes back is fixed against your facts rather than adapted to them afterwards.

The Yard That Learned Late

A short case, because it is common. A yard ordered a 400-class machine with a 30 kW motor on a supply that could start it — but the yard’s load had grown since the supply was last assessed, and the peak-day capacity was not what the invoice assumed. The machine arrived, the motor stalled on the first heavy start, and the upgrade was bought at emergency prices with the production plan waiting. The whole cost was one phone call that never happened: the electrician’s assessment of spare kilowatts at peak, before the build.

The case is not about the machine or the factory — it is about the moment the supply conversation happens. At quotation it is free; at delivery it is a project. The three numbers from your electrician close it, and the configuration that comes back is fixed against your facts rather than adapted to them afterwards.

The Supply as a Specification

The supply is a specification item rather than a site detail, and it is fixed before the build along with everything else. The three numbers from your electrician — voltage, frequency, spare kilowatts — pick the motor package, the starting method and the protection arrangement, and the electrical scope that comes back is the document your contractor verifies the installation against.

Send the three numbers with the inquiry and the scope comes back in writing before the machine is built. The starting-methods guide covers the mill-scale version of the conversation, and the configuration that ships is fixed against your facts rather than adapted to them afterwards.

Buyer FAQ

Which motor configuration should I choose?

The one your supply starts cleanly and your tonnage justifies. Send voltage, frequency and spare kilowatts with the inquiry and the configuration is confirmed in writing before the build.

What is the difference between the kW options?

Site suitability, not capability. Lower kW suits generator or diesel supplies; higher kW suits grid-connected yards with throughput ambitions; the twin-motor option splits the starting demand.

Can the motor be changed after delivery?

Not practically — motor rating, voltage, frequency and power source are build decisions. The configuration is fixed at quotation against your site facts.

What does my electrician need to confirm?

Three numbers: available voltage and frequency, spare capacity in kilowatts after the yard’s existing load, and the starting method the supply can deliver.

Does a bigger motor cut more material?

No — the force rating is the force rating. The motor package decides whether the machine starts cleanly and runs steadily on your supply, which is a site question rather than a capability one. Send the three numbers from your electrician with the inquiry, and the electrical scope comes back confirmed in writing before the build — the supply conversation is free at quotation and a project at delivery. Send the three numbers from your electrician with the inquiry and the electrical scope comes back confirmed in writing before the machine is built — the supply conversation is free at quotation and a project at delivery.