Meaning of BELT HORSEPOWER?

richard d hayes · Jun 17, 2014

Recently I have been looking at some of the statistics for the old Ford Tractors. I can understand the meaning of horsepower and PTO HP, but don't know the meaning of belt or pulley horse power. (they always seem to be lower than the PTO HP) When I was about 5, my grandfather took me to a hay field where bailing was taking place with a Farmall M and a IH Type 15 hay press. This setup had a power take off (drum) on the side of the tractor and a large fly wheel on the bailer with a leather belt running between the two. I am guessing that this is not the type of belt HP they are talking about. Any explanation or help with its meaning or application would be appreciated.

Ecnerwal · Jun 17, 2014

Contrariwise, that's exactly the type of power they are talking about - so you can justify that shiny new tractor to the wife by saying "but dear, it will also replace the 15 horse stationary engine we've been using to..."

Sean in PA · Jun 17, 2014

The Ford tractors after 1939 (9N and up) all had a PTO shaft out the back, but they also had an optional pulley drive gearbox that was driven by the PTO and provided a pulley for a wide flat belt to drive belt driven implements or whatever you already had on your farm that used a belt drive. John Smith has a picture of one about two thirds of the way down his accessories page [u:ef3b31b387]Here[/u:ef3b31b387]. The gear boxes lost a little of the PTO power to heat and inefficiencies of the gears, so the belt hp was always tested/rated separately from the PTO hp.

sumbeam · Jun 17, 2014

Belt pulleys were much more common on early tractors than PTO.

Graham from New Zealand · Jun 17, 2014

Before we heard of the Ferguson tractors in New Zealand all tractors I knew of had the belt pulley mounted on the RH side of the tractor just behind the clutch and were rated a little higher than the PTO figure because it was a simple bevel drive off the front of the transmission with less power loss than the PTO drive train gears. We used a MM RTU to drive a large hay baler with the belt pulley. The Ferguson system lost even more power in the belt pulley because of the extra right angle drive gearbox on the PTO to drive it.

Anonymous-0 · Jun 17, 2014

Belt horsepower is pretty much the engine horse power available. The belt, or PTO out the rear, is where this would be tested from.

The other measurment of a tractor is drawbar horsepower. This involves the maximum ability to pull a dead weight. The test peaks when the wheels spin without the tractor moving forward, or the engine stalls. It is always less than the engine horsepower.

Tractors up till the 1930's used to be rated for both, thus you'd see tractors listed as a 10-20, 20-35, with the first number being dawbar, the second, belt.

Pete

Meaning of BELT HORSEPOWER?

richard d hayes

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Ecnerwal

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Sean in PA

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sumbeam

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Graham from New Zealand

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Anonymous-0

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