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How to specify a Motor Capacitor

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

25 Oct 2026 · 3 min read · Tradinor Desk

Specification points for Motor CapacitorTRADINOR · FIGUREWhat to lock for Motor CapacitorPower and speedElectricalDutyEnclosure
Put these on the RFQ for Motor Capacitor before you compare prices.

A buyer searching for Motor Capacitor 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 a Motor Capacitor. 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 Motor Capacitor

A motor is specified by power, speed, voltage, duty, and the mechanical interface. For a Motor Capacitor, 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.

Motor Capacitor is easy to confuse with RC Motor. 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 Motor Capacitor
Power and speed Kilowatts or horsepower and rpm at the rated point.
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.

How to compare two offers

Lay both quotes for Motor Capacitor on one sheet and line up power and speed, electrical, and duty. 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 Motor Capacitor with a cheaper line that omitted power and speed.

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 Motor Capacitor 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

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

On a Motor Capacitor, 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: “Motor Capacitor — 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 Motor Capacitor: waterproof / IP65, or IP67. 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. IP67 is dust-tight plus a defined temporary immersion. It is not a rating for living underwater, and it says nothing about sunlight or salt. 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 RC Motor.

Questions buyers actually ask

What should an RFQ for Motor Capacitor include?

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

Is a cheaper Motor Capacitor the same part?

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

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

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