Today’s planters and the hydraulically powered systems paired with them demand careful consideration to ensure enough hydraulic capacity.
Compatibility isn’t a problem just for husbands and wives.
In a machinery relationship, there’s a reason many modern planters are pulled by late-model tractors. It’s because it takes a tractor with enhanced hydraulics to satisfy the
demands of planters with multiple hydraulically powered systems.
“Vacuum metering systems can require up to 13 gal. per minute of hydraulic flow, bulk fill systems add another 10 gal., each hydraulic drive will require 3 gal. to 4 gal., and to lift and lower a planter with markers could require 13 gal. to 20 gal., depending on planter size,” explains Alan Forbes, planter marketing manager for Case IH. When all the hydraulic demands are tallied, modern planters can require more than 35 gal. of oil per minute from tractors at more than 2,200 psi of pressure.
Adequate hydraulic flow and pressure are only the first steps toward tractor/planter hydraulic compatibility. Tractors must have enough selective control valves (SCVs) to accommodate three or more sets of hydraulic hoses. Newer planters require tractors to have special case drain and motor-return hydraulic couplers.
Fortunately, all of the major planter manufacturers have developed hydraulic compatibility charts for their product lines. Those charts define how many gallons per minute of hydraulic flow tractors must provide and how many SCVs are needed, depending on how many hydraulic systems an individual planter uses.
“A tractor may have the horse-power to pull the planter, but not the capacity to operate it. For every gallon of hydraulic oil that machine is taking in, it requires about 1 hp,” Forbes says.
Tractor and planter compatibility charts are a good starting point, but don’t expect instant hydraulic bliss.
Hydraulic checkup. A tractor may have enough SCVs but not enough hydraulic capacity to make all the planter’s hydraulic systems work correctly, says Laura Blomme, marketing specialist for Kinze Manufacturing.
“[Local dealerships have] ran tests and found that tractors’ hydraulic systems weren’t working to full capacity, or were worn and couldn’t produce full flow and pressure. Growers need to have their dealer check to see what their tractor can actually do hydraulically, and not just what its specs were from the factory,” Blomme says.
Older tractors may simply not have enough SCVs. Some farmers add power beyond–type hydraulic systems to sidestep the cost of adding SCVs.
Power beyond systems are essentially hydraulic couplers plumbed directly into the hydraulic system. The couplers and anything connected to them receive full hydraulic flow and pressure when the tractor is running.
“I’m not a great fan of power beyond because it puts full flow and pressure to a planter’s hydraulic motors, and that can cause problems for vacuum fan motors and variable-rate-drive motors that don’t need full flow,” says Jared Matthews, service manager at Sloan Implement’s
Assumption, Ill., dealership. “I prefer to install additional SCV blocks. SCVs give hydraulic motors controlled flow, and it’s an all-around better deal.”
Even with adequate hydraulic capacity and ample SCVs on their tractors, farmers with new planters may discover they have extra hoses that need to be connected to their tractor.
“The new hydraulic motors are a double-seal design that use controlled leakage to lubricate the motors,” says Matt Winters, a field service representative for Great Plains Manufacturing.
“That’s what the third hose on new-style hydraulic motors is for. There’s almost no volume in that extra return hose. Maybe a drop or two [of hydraulic oil] a minute. But if there’s any
restriction, that little bit of oil can build up during a day of planting, create backpressure and take out the seals in the hydraulic motor.”
That’s why many modern tractors have case drain (also known as sump return) ports outfitted with special hydraulic couplers. The couplers dump directly into the tractor’s hydraulic sump/reservoir to ensure minimal backpressure on the hydraulic circuit.
Case drain hydraulic circuits differ from motor-return circuits. Motor-return is a fancy name for the traditional hydraulic circuit that returns pressurized oil from hydraulic motors back to the tractor. On some modern planters, motor-return hoses may need to be connected to special
motor-return hydraulic couplers on tractors.
“Going through the ports and orifices of an SCV can build up to 1,800 psi to 2,000 psi of backpressure,” explains Sloan Implement’s Matthews. “Some [hydraulic] motors can’t take that sort of pressure on their return circuits. You’ve got to read the [planter’s] owner’s manual, and if that type of hydraulic motor needs to be connected to a designated motor-return port, you’ve got to make sure the tractor has a motor-return coupler and that the right hoses are plugged into it.”
It’s important to connect case drain and motor-return hoses to the correct ports.
“A motor-return port usually carries around 200 psi to 300 psi,” says Great Plains’ Winters. “Case drain ports have next to no resistance. Plug a case drain hose into a motor-return port and it will take out the [hydraulic motor] seals instantly.”
Sometimes planter hydraulic systems don’t work correctly even if the tractor has adequate flow and pressure and all of the hydraulic hoses are plugged into appropriate SCV couplers. Greg Brenneman, marketing manager for Great Plains Manufacturing, says adjustment of hydraulic controls in the tractor’s cab is critical.
“Strange things can happen if you have the controls set for full flow of 30 gal. per minute, but the variable-rate-drive motor only needs 6 gal. per minute,” he says. Hydraulically powered vacuum fans and variable-rate-drive motors operate at low volume but high pressure. Excessive flow can cause erratic performance.
Brenneman suggests farmers who buy a new planter or trade for a used one work with their dealer to match the planter’s hydraulic needs with their tractor’s hydraulic capabilities.
“Depending on the size of the planter and what hydraulic systems you have on it, you’re probably going to need at least 30 gal., maybe 35 gal., per minute of hydraulic capacity and four SCVs,” he says. “You also need to know if your tractor is open-center or closed-center hydraulics.
“The bottom line,” Brenneman says, “is to make certain your tractor and planter hydraulics are compatible and connected correctly, long before you head to the field.”
Avoid Electrical Headaches
Hydraulics aren’t the only tractor system taxed by large modern planters. Electric row shutoffs, on-board air compressors, aftermarket monitoring systems and extra lights on planters can add amps that overload tractor electrical systems.
Symptoms that indicate an overloaded electrical system include row shutoffs that operate erratically, air compressor motors that overheat, blown fuses, tripped circuit breakers and monitoring systems that give erratic or odd warnings or alarms. A dead giveaway of an overloaded electrical system is when any of these symptoms develop at sunset, coincidental to switching on the tractor’s lighting system.
“We’re going to see more stress on tractor electrical systems because there are more planter and seeder control systems coming down the road that are really going to increase the demands on tractor electrical systems,” says Matt Winters, a field service representative for Great Plains Manufacturing. “If you’re going to trade for a planter that has more electrically controlled systems, or if you’re thinking of adding row shutoffs or other electrical components, it’s a good idea to check ahead of time to make sure your tractor has a big enough alternator and electrical system to power the additional electrical components.”
- Machinery Guide 2011