Electric motor RFQ checklist: the details suppliers need

A motor inquiry often starts with a power rating and a photograph. Those can identify a product family, but they rarely define a complete purchase. Two quotations may appear comparable while covering different mounting arrangements, controls, accessories or acceptance conditions.

This guide helps procurement and engineering teams prepare one consistent brief. The aim is to make supplier differences visible before a sample order, rather than discovering them during assembly. Treat every unspecified field as an open question, and ask each supplier to state its assumptions in the quotation.

The checklist at a glance

Copy these fields into your inquiry and fill in what you know. Where a value is not settled, write "unknown" or "supplier to propose" instead of leaving it out, so every quotation answers the same questions.

Machine and task: what the motor drives, whether it is a new design or a replacement, and what must stay interchangeable
Scope of supply: motor only, or motor with gearbox, brake, encoder, controller, cable and connectors
Electrical supply: voltage, phase and frequency, plus the controller or inverter the motor will run on
Output: required speed, continuous and peak torque, and how the load changes through the cycle
Mounting: shaft, flange or feet, fixing holes and the space available, with a drawing reference
Duty: hours per day, starts per hour, idle periods and braking
Environment: ambient temperature, site altitude, water, dust, chemicals, washdown and any hazardous-area classification
Compliance: the markets the machine is sold in, the efficiency class required there, and the certificates or test reports the offered model must carry
Commercial: sample quantity, first order, expected yearly demand, delivery destination and target date
Documents to request: datasheet, outline drawing with revision, wiring diagram and test report for the offered model

The sections below explain what to put in each field and what to ask suppliers to confirm.

Start with the machine and its operating task

Describe what the motor drives. A pump, conveyor, washing machine and positioning axis raise different selection questions. Include the load, expected operating pattern, installation space and any existing machine interface. A replacement project should identify what must remain interchangeable; a new design should distinguish fixed requirements from dimensions that can still change.

Explain whether your request covers only the motor or a complete drive package. If a gearbox, brake, encoder, controller, cable or connector is required, list each item. A catalogue photograph is useful as a reference, but it is not a substitute for a bill of materials and an approved drawing.

Separate requirements from preferences

Mark which conditions are mandatory and which are negotiable. For example, a mounting interface may be fixed by an existing assembly while the supplier can propose a different winding or connector. This avoids rejecting a workable alternative merely because its catalogue description uses different terminology.

Document the electrical supply and controls

State the available supply, phase and frequency, together with any permitted variation defined by the project. If the motor operates with a controller or inverter, identify the controller and provide its relevant documentation. Ask the supplier to confirm the proposed motor and controller combination rather than assuming two separately quoted parts form a compatible system.

For electronically controlled motors, include the command interface and feedback requirements. Request connector pinouts and the applicable wiring diagram. Record whether the controller is included in the commercial price, supplied separately or expected to be provided by your engineering team.

Define mechanical output and installation

Provide the required operating speed and load information from the machine specification. Where torque varies through a cycle, share the profile rather than a single peak value. Ask the supplier to identify continuous and intermittent limits in the offered configuration and to explain which operating conditions those limits depend on.

Attach a dimensioned drawing for the shaft, flange, mounting holes and available installation envelope. Include coupling and gearbox interfaces where relevant. Ask for a proposed outline drawing with a revision identifier, then include the accepted revision in the eventual purchase documentation.

Describe duty and the operating environment

Document the operating cycle, starts and stops, intended hours of use and expected idle periods. Record the ambient conditions and any exposure to water, dust, chemicals or washdown. If the machine will run well above sea level, give the site altitude, because catalogue ratings assume standard site conditions and the supplier may need to confirm the rating for yours. If the application involves a hazardous location, give the project classification and involve the responsible technical specialist in evaluating the offered equipment.

Do not translate a generic phrase such as “industrial use” into an assumed protection rating. Ask for the exact rating and supporting documentation for the proposed model. A certificate for a company or a different product family does not by itself describe the motor in your quotation.

Make commercial quotations comparable

Give the sample quantity, expected initial order and approximate recurring demand if known. State the delivery destination and ask each supplier to identify the delivery basis, packaging, quotation currency, validity and lead time. Keep tooling, development charges, accessories and recurring unit cost as separate entries.

Ask what happens between a sample approval and a production release. Establish which drawings, test results or signed specifications must be agreed before manufacturing. Include the procedure for notifying you of a material or component change that affects the approved configuration.

Request documents tied to the offered model

A useful response should identify the manufacturer, model, configuration and revision. Request the current datasheet, dimensional drawing, connection information and relevant test or conformity documents. Keep the document version beside the quotation so later comparisons use the same reference. If the machine is sold into a market with a minimum motor efficiency class or a required certification, name that market and ask which class and certificates apply to the offered model, not to the supplier's range in general.

If a requirement remains unconfirmed, label it explicitly. A blank field should not be read as approval. Before selecting a supplier, resolve differences in technical scope and document which questions remain for sample evaluation.

A lifting-drive brief in practice

For a hoist or crane, a nameplate power is only one field. The crane-duty motor RFQ guide adds the movement cycle, starts, braking and control scheme to the general worksheet above. Use a YZ crane-motor series or YZR wound-rotor series as a research starting point, then ask the supplier for a model-specific rating and drawing against your load profile. These series links do not establish interchangeability or suitability for any particular lifting machine.

Sending the brief through MotorSourcing

Shortlist suppliers from the manufacturer directory or a motor type page, using the Add to inquiry button on a manufacturer or product page. The inquiry form asks for a subject, quantity, destination country and a specification field, so the checklist above can be pasted into it as written. No account is needed: send it with your name, company and work email, and the reply comes by email. Your contact details are not published on the site.

When replies arrive, compare each one against the same brief and keep every supplier's configuration and clarifications separate, so an alternative offer is visible as an alternative rather than blending into the baseline. To judge the companies themselves rather than their quotations, see how to compare motor manufacturers. If a catalogue lists a series instead of an orderable code, motor series vs. exact model covers what to pin down before asking for a price.

The directory is a starting point for research. Manufacturer catalogue information can help identify candidate product families; suitability, availability and final commercial terms still need confirmation with the selected supplier. Save the approved specification with your purchasing records before placing the order.