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How to specify an AC Motor

What to put on an RFQ for AC Motor: the ratings, documents, and constraints that change the quote.

25 Oct 2026 · 3 min read · Tradinor Desk

Specification points for AC MotorTRADINOR · FIGUREWhat to lock for AC MotorElectricalDutyEnclosureInterface
Put these on the RFQ for AC Motor before you compare prices.

A buyer searching for AC Motor is usually trying to stop a bad substitute. A motor is specified by power, speed, voltage, duty, and the mechanical interface. The notes below are selection criteria for an AC Motor. They are not a catalog promise. Confirm every rating on the current datasheet, drawing, or test report for the revision you will receive.

What has to be true of AC Motor

A motor is specified by power, speed, voltage, duty, and the mechanical interface. For an AC Motor, start from the duty, then the interface to the rest of the machine or the room, then the document that proves the claim. A lower price that leaves one of those blank is a different product.

AC Motor is easy to confuse with Hub Motor Motors. If the quote could be read as either, add the line that separates them: the rating, the fitment, or the standard named below. Link the drawing number to that line so receiving inspection can reject the wrong one.

Numbers that change the quote

Line What to write for AC Motor
Electrical Voltage, phases, frequency, and current.
Duty Continuous or intermittent, and the ambient.
Enclosure The enclosure code and the mounting, such as foot or flange.
Interface Shaft size, and feedback if it is a servo.
Drive Whether it will run on a VFD. Insulation and bearing measures may change.
Power and speed Kilowatts or horsepower and rpm at the rated point.

How to compare two offers

Lay both quotes for AC Motor on one sheet and line up electrical, duty, and enclosure. If a cell is empty, the offer is not finished. Ask for the missing line in writing. When those match, the honest difference is lead time, the test evidence, and who carries the warranty. Do not average a fully specified AC Motor with a cheaper line that omitted electrical.

Documents worth having before the deposit

IEC 60034 is the usual rotating-machinery family. Ask which ratings on the nameplate follow it. The file should name AC Motor and the revision, not only the supplier’s homepage. A factory quality certificate such as ISO 9001 can sit beside that file. It does not replace it.

Failures that show up after delivery

  • Forgetting the service factor or the duty.
  • Putting a standard motor on a VFD without asking about insulation and bearings.
  • Mismatching the shaft.

On an AC Motor, the expensive version of the first mistake is discovering it after the goods are in the crate. Put the rejection condition in the purchase order while the supplier can still restate the offer.

A worked RFQ line

Use this shape, then replace the brackets with your duty: “AC Motor — State power, speed, voltage, phases, duty, and frame or shaft.” That sentence is a template, not a rating of any brand. If a supplier’s datasheet uses different units, convert them onto this sheet so the next offer can be compared.

Where words like waterproof / IP65 belong

Searches often add a constraint to AC Motor: waterproof / IP65, or OEM / custom. Keep those on this page. IP65 in IEC 60529 means dust-tight and protected against water jets. Write that code if hoses are the real exposure. The word waterproof alone does not name a test. OEM or custom means a drawing, a revision, and a statement of who owns the tool. Without those, you are buying the catalog part. If you need a third constraint, add it as another line on the same drawing. A second URL that only swaps the adjective does not give a buyer a second fact.

Related in this section: how to specify Hub Motor Motors.

Questions buyers actually ask

What should an RFQ for AC Motor include?

State power, speed, voltage, phases, duty, and frame or shaft.

Is a cheaper AC Motor the same part?

Only if electrical, duty, and the documents match. A missing line is a different offer.

Do waterproof, OEM, or IP words need their own page?

No. For AC Motor they are extra lines on this specification. Ask for the test or the drawing that gives the word a value.