Work out chain tension from power and speed, then check the chain.
Use the motor rating, not the average load.
These limits are for power transmission. Chains that lift or suspend a load follow different rules, so never size a lifting chain with this page.
Example Result
Your result will appear here
The calculated result will appear here after you press Calculate.
Chain pull is the force a chain carries on its tight side to transmit power. It is power divided by chain speed: F = P ÷ v. Enter the power and the speed, or the chain pitch, sprocket teeth and rpm. You get the pull in newtons and pounds-force, and the breaking strength your chain needs.
Enter the motor rating, not the average power of the job.
Add the service factor from the chain maker for your type of load.
Enter the chain speed, or the sprocket teeth and rpm.
Choose the chain and the type of connecting link.
Press Calculate to see the pull and the breaking strength you need.
By O.E. — Partner, chairman of the board and CEO of a metal products manufacturer for 21 years; the company exports to 45 countries.
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F = P ÷ v = 5,500 W ÷ 3 m/s = 1,833 N, or 412 lbf.
In US units there is a convenient form: F = 33,000 × hp ÷ ft/min. For 10 hp at 590 ft/min, F = 33,000 × 10 ÷ 590 = 559 lbf.
The same power at half the speed means twice the pull. That is why a slow final drive needs a much heavier chain than a fast one.
If you know the sprocket and not the speed: v = pitch × teeth × rpm ÷ 60. For a #40 chain (12.7 mm pitch) on 17 teeth at 700 rpm, v = 0.0127 × 17 × 700 ÷ 60 = 2.52 m/s.
Use the motor's rated power, not the average power of the job. Motors can deliver well above their rating when starting, and a jam or a shock load goes straight through the chain. Multiply by the service factor from the chain maker for your type of load.
Compare the pull with the chain's minimum breaking strength. Diamond Chain, a US maker, keeps chain pull below a fraction of that strength, and the fraction depends on the connecting link:
| Connecting link | Keep pull below |
|---|---|
| Press-fit | 1/6 of breaking strength |
| Slip-fit or offset | 1/9 of breaking strength |
A joint is the weakest part of a chain, so an offset link costs you a third of the allowable load.
For the 1,833 N drive:
ANSI chain has a minimum breaking strength of about 12,500 × p² lbf, with p in inches.
| Chain | Pitch | Breaking strength |
|---|---|---|
| #40 | ½ in | 3,125 lbf (13.9 kN) |
| #50 | ⅝ in | 4,883 lbf (21.7 kN) |
So #40 passes with press-fit links, and the slip-fit version has to move up to #50. Check the figures for your exact chain, since makers publish their own.
This check covers breaking only. A chain usually wears out long before it snaps, so the power rating tables from the maker set the real size. The chain drive speed calculator covers wear limits, chain length and centre distance.
These limits are for power transmission. Chains that lift or suspend a load follow different rules, so never size a lifting chain with this page.
A moving chain carries extra tension from its own mass: T = m × v², with m in kg per metre. On the sprocket this adds to both sides.
For #40 at about 0.65 kg/m and 3 m/s, T = 0.65 × 9 = 5.9 N, which is 0.3% of the 1,833 N pull. At 10 m/s it is 65 N. It matters on fast drives and can be ignored on slow ones. The chain weight calculator gives the mass per metre.
The sprockets pass the pull to their shafts as a side load, so the bearings on both shafts carry it. A sagging or over-tightened chain adds more. Use the pull as the starting load in the bearing life calculator. To turn power and rpm into torque at the sprocket, use the torque calculator.
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