Saturday, August 1, 2015

Hey Grinderguy, should I buy a 750 or 1000 horsepower grinder?

Great question and a lot of other people are in the same situation you are. What to do?
 Let’s assume price doesn’t matter and that you can afford the $150-200,000 price difference. What are the differences?
·         Production- This is the only reason you would purchase a 1000 horsepower(HP) engine over a 750 HP engine. Obviously a 1000 HP grinder can grind more than a 750 HP machine. How much more is dependent on the grinder, the material and the screen size?
But at what cost?
·         Fuel- You won’t use double the fuel with a 1000 HP grinder, but 50% or more is easy to do.
·         Filters, Parts, Etc. – There are more filters with a 1000 HP engine than a 750 HP engine, along with more oil, pistons, liners, etc. So your maintenance costs are going to be higher.

What are things to consider and questions to answer and before deciding on engine horsepower?
·         Is the rotor, hammermill or chipper drum the same for a 1000 HP machine as a 750 HP machine? If they are the same, getting that weight to spin at maximum rpm will be much easier to do with a 1000 HP engine. Typically, they are not the same. The 750 HP machine would, in general, have a smaller diameter, width and weight than a 1000 HP machine.
·         Engine RPM- A 1000+ HP grinder will have 12 cylinders, compared to 6 cylinders on a 750 HP machine. So being able to get back to maximum rpm or maintain rpm is much easier to do with 6 cylinders.
·         Fuel- A 1000 HP engine will use 300-400 gallons of fuel per day. Do you have the ability to fuel the machine efficiently every day? Using a 100 gallon tank in the back of a pickup truck will take 3 or 4 trips to the Gas Station every day.
·         Moving Equipment- Usually the higher HP machines are much heavier and take trucks with an extra axle or more permitting than the lower HP machines, all which includes extra expenses.
·         Computer Controls- With Automatic Feed Systems monitoring the engine rpm, engine load and infeed belt speeds, it is much easier to maximize the production with the lower HP machines so they can grind almost as well as a 1000+ HP machine.
·         Support Equipment- This is the number one issue and should be the number one factor in your decision. Consider for example, a 1000 HP machine, would grind 100 ton per hour(TPH). This means, the log loader, wheel loader or excavator feeding the grinder would need to be able to load 100 TPH into the grinder. You would also need to remove 100 TPH from underneath the discharge conveyor and you will need 100 TPH within reach to load in the infeed. 100 TPH every hour of every day. If this is not possible, why bother with the 1000+ HP. Most companies do not maximize a 750 HP grinder.
I have customers that swear their 750 HP machine grinds equal to their 1000 HP machine. Again, it really depends on what grinder, what material and what screen size. But the computerized grinder infeed systems can make all the difference in the world. They are not all the same. They may use the same brand of computer system, but the actual programming and monitoring is what makes the difference. Some companies do a much better job in their electrical controls department than other companies. If you haven’t run them all before, you won’t know the difference. But when you run more than one, you will notice who has the better mousetrap. And it is significant.
In either case, when you decide on a engine manufacturer or horsepower, be sure to purchase the extended warranty. As much as you can afford! It is not IF the engine is going to need repaired or replaced, it is WHEN is it going to need repaired or replaced. BUY THE WARRANTY!!

Questions? Dave Whitelaw, grinderguy@askthegrinderguy.com