Generator buying guide: compare a complete quotation

Start with the equipment you need to power

A useful generator enquiry starts with the application. Explain whether the unit is for occasional backup, mobile work or another operating pattern. List the equipment that may run together and share its nameplate information. Ask the supplier to check the proposed generator against those loads and the equipment instructions before selecting a configuration.

• Identify loads that start together and equipment with a separate starting requirement.
• State the expected hours of use, location and relevant operating conditions.

Keep rated output and maximum output separate

Compare offers using the same power definitions and units. Record the rated output separately from any maximum or starting figure, and ask how each figure is defined for the quoted model. If one offer uses kW and another uses kVA, request the corresponding values and stated power factor before treating them as equivalent.

• Ask which output is available for the intended operating pattern.
• Request any stated limits or conditions affecting the quoted output.

Check W and VA before adding loads

Use the equipment's electrical input power for your load list. For single-phase AC, voltage multiplied by current gives apparent power in VA. Real power in W equals VA multiplied by the power factor. If the power factor is unknown, keep the voltage and current beside the nameplate photograph for review. A motor's mechanical output in kW or hp is a different quantity from its electrical input.

• Record W or kW separately from VA or kVA; 1 kW = 1,000 W and 1 kVA = 1,000 VA.
• Ask for both the running and starting requirements of motor-driven equipment. Keep each requirement's unit and source.
• Have the supplier check current limits and motor-starting behaviour as well as the total W.

Active and apparent power explained (Schneider Electric)

Calculate a running load and a starting event

The following numbers are hypothetical planning inputs, not VEGA specifications or typical appliance ratings. Assume the lights and chargers are already running when one pump starts. The pump's 2,000 W starting figure means its total input during that event. Replace every value with data from your equipment manufacturer before requesting a model recommendation.

• Additional starting demand for the pump: 2,000 - 750 = 1,250 W.
• Combined running load: 200 + 100 + 750 = 1,050 W.
• Demand while the pump starts: 200 + 100 + 2,000 = 2,300 W. The same result is 1,050 + 1,250 = 2,300 W.
• If other motors can start or restart at the same time, review that combined event separately. Ask the supplier to check starting duration, current, voltage response and the proposed generator configuration.

Generator load worksheet reference (Generac)

Specify the electrical configuration

The same model name can appear in quotations for different markets. Confirm the voltage, frequency, phase and socket arrangement on the actual order specification. If comparing inverter and conventional designs, ask for the output characteristics relevant to your equipment instead of relying only on the product label.

• Confirm socket types and any individual outlet output limits.
• For a waveform or THD claim, request the test conditions and applicable model.

Compare BS4500IE and BS6500 against your load sheet

The BS4500IE page lists 3.5 kW rated output; the BS6500 page lists 5 kW. Use their specification pages as references for a quotation. Ask for a written review of your actual loads and the electrical configuration for your destination. The hypothetical example above does not establish that either model will start or run your equipment.

• Confirm the quoted running output, voltage, frequency, phase and outlet limits together.
• Ask what starting demand the specific configuration can support and under which conditions. A catalogue maximum-output figure alone does not establish that capability.

• BS4500IE model specifications
• BS6500 model specifications

Make noise and runtime figures comparable

A noise or runtime figure needs context to be useful. Ask for the load, measurement method and configuration behind it. Noise measured at different distances and runtime measured at different loads are not direct comparisons. Keep those conditions beside the headline figures in your purchasing worksheet.

• Noise: request measurement distance, operating load and the quantity reported.
• Runtime: request operating load, fuel quantity and test conditions.

Confirm the package and acceptance record

Bring the engine identification, starting system, dimensions and weights into the quotation. Separate included items from options, especially batteries, wheels, handles and connection accessories. Agree which specification, photographs and inspection record will identify the supplied configuration, then keep that record with the order.

• Distinguish net machine weight from packed weight and dimensions.
• Confirm the supplied manual language, model identification and accessory list.
• Discuss matching service parts and written warranty terms before ordering.

Copy this load and quotation worksheet

Copy these fields into your enquiry. Repeat the equipment row for every load and attach nameplate photographs or manufacturer data. Mark missing starting information as unknown. Ask the supplier to return a model-specific quotation with confirmed details and open questions.

• Destination country and port: [ ]; application: [ ]; hours of use: [ ]; site altitude and ambient temperature, if known: [ ].
• Required voltage: [ ]; frequency: [ ]; phase: [ ]; plug/socket type: [ ].
• Equipment row: model [ ]; quantity [ ]; electrical input W per unit [ ]; VA or input current A per unit [ ]; voltage [ ]; power factor, if known [ ]; data source [ ].
• Starting row for each motor: total starting W, or additional starting W clearly labelled [ ]; starting current A if supplied [ ]; duration if supplied [ ]; equipment that may start together [ ].
• Loads expected to run together: [ ]; operating priorities or agreed start sequence: [ ]; future loads to review: [ ].
• Preferred generator reference: [ ]; quantity: [ ]; starting method: [ ]; accessories: [ ]; packaging, branding and manual language: [ ].
• Requested delivery timing: [ ]; sample or inspection needs: [ ]. Please confirm MOQ, lead time, quotation validity, warranty, shipment and payment terms in writing.

Choose a product mix for your customers

Inverter vs conventional generators: a wholesale buying guide ↗