Selection Guide · Frequency
50 Hz vs 60 Hz: Frequency Sets the Field Speed
Every catalogue listing in this range states “50/60 Hz”. What that combined line does and does not establish is this guide’s subject: it states the range’s frequency options, and it does not by itself say whether a given model is rated for one frequency or for both — that rating is confirmed per model, in the quotation. What follows explains what supply frequency actually changes inside an induction motor, and why the destination frequency belongs in every motor order.
01 The Physics
Frequency is speed
An induction motor’s rotating field is locked to the supply frequency it is actually connected to: the field’s speed is that supply frequency divided by the motor’s pole pairs. Connect the same motor to a 60 Hz supply and its field runs about a fifth faster than when it is connected to a 50 Hz supply; connect it to a 50 Hz supply and it runs at the 50 Hz field speed — whatever frequency is printed in the motor’s rating. The rating label does not set the speed; the supply does. Two speeds must not be confused here: the rotating field’s speed is the synchronous speed, fixed exactly by the supply frequency and the pole count, while the rotor — and with it the shaft — turns a little slower, by the slip an induction motor needs to produce torque. The 60/50 ratio is exact for the synchronous speed; shaft speeds follow it approximately, and they also move slightly with load, because slip moves with load. Everything geared to that shaft — the drum’s wash and spin speeds through a fixed belt ratio, a fan’s airflow (which rises steeply with speed), a pump’s delivery — moves with the actual supply frequency.
Frequency also enters the magnetic design. The core’s flux depends on the ratio of voltage to frequency: run a winding designed for 50 Hz on 60 Hz at the same voltage and the flux falls (the motor runs weaker); run a 60 Hz design on 50 Hz and the flux rises toward saturation (the motor runs hot). Competent makers therefore treat voltage-and-frequency as one combined rating — which is why this catalogue lists voltage options (220–240 V / 110 V) and frequency options (50/60 Hz) as a set to be specified together, and why its text offers customisation of voltage, frequency and rotation speed as one conversation.
02 Ordering
How frequency should appear in your programme
- Name the destination market’s supply: nominal voltage and frequency together — “220–240 V, 50 Hz” is a specification; “220 V” alone is half of one
- One programme, two frequencies: manufacturers selling into both 50 Hz and 60 Hz markets state both destination ratings in the programme. Whether a model is supplied as a dual-rated unit or as separately rated variants is not stated in the listings — it is confirmed per model in the quotation, and the programme is priced once that rating basis is fixed
- Check the driven speeds: if your machine’s spin speed or programme timing is frequency-sensitive, say so — the motor’s speed point is part of the match, and pulley ratios in belt drives are chosen against it
- Samples in the right rating: validate samples wound for your market’s frequency; a 60 Hz sample proves little about a 50 Hz production motor’s behaviour in your machine
Regional shorthand for the specifier: most of Europe, Asia, Africa and Oceania runs 50 Hz; the Americas and parts of Asia run 60 Hz — but the order document should always carry the numbers, not the geography.
03 Questions
Frequency, answered plainly
The listing says 50/60 Hz — can one motor really serve both?
The listing states the range covers both frequencies; it does not state whether an individual model is rated for one frequency or for both, and this page does not assume either. State your market’s frequency in the order and the model’s rating for that supply is confirmed in the quotation, in writing. Order by the confirmed market rating, not by the catalogue’s combined line.
What happens if a 50 Hz market receives motors rated for 60 Hz?
Receiving them changes nothing by itself: speed is set by the supply, so on a 50 Hz supply the motor runs at the 50 Hz speed, not a fifth faster. The real risk is the rating mismatch — a winding designed for 60 Hz, run on 50 Hz at the same voltage, sees its flux rise toward saturation and can run hot, and its rated data no longer describes it. That is why the order states the market’s supply voltage and frequency together, and the rating confirmed for that supply is stated in the quotation.
Can you wind for less common ratings?
The catalogue offers customisation of voltage, frequency and speed to order. State the target rating in the enquiry; the winding is confirmed in the quotation.
Put the frequency in the enquiry
Voltage and frequency together, plus the model and quantity — the quotation then confirms a winding rated for your market, in writing.