What are Power Take Offs? Learning about Chelsea PTOs from Parker

Hi Lifco Fans; we just started carrying a new line of products for mobile applications. To find out more, I chatted with Fraser about these Chelsea Power Take Offs from Parker. 

Tomas: Hi Fraser, I heard we are carrying a new line of products from Chelsea (PTO?), what sets this line apart, and why did you decide to start stocking these?

Fraser: Chelsea PTO's are not hydraulic. They are a mechanical device, much like a gearbox. But they are critical for mounting a hydraulic pump onto a truck with a transmission. This is in a field called "On Highway" or "Vocational Truck" or often just called "Truck.

Tomas: I imagine a lot of the mobile trucks and machines that we saw at ConExpo required something similar?

Fraser: The PTO connects a hydraulic pump to the truck transmission. Allowing it to be driven by the same engine that is driving the wheels. But there are lots of variations in where and how it does it.

Tomas: So unlike an excavator for example, where a diesel engine powers the hydraulic tracks, in this case, the vehicle would have a standard transmission but still be able to operate hydraulic actuators because of the PTO? Would something like a street-sweeper utilize this?

Fraser: In an excavator there is an engine and it is coupled to a series of hydraulic pumps, which have hoses to the different valves and components like motors and cylinders. In an on-highway truck, the engine is connected to a transmission because the wheels need to spin at a few miles per hour and at 100 miles per hour. This PTO connects to that transmission and allows some of that power to then go to a hydraulic pump.

If the PTO did not exist then the hydraulics would need it own diesel or gas engine

Tomas: Is this the first time Lifco is carrying PTOs? Since we are a Parker service center, will we be doing any inspections, tests, or repairs on this line?

Fraser: It is a very simple product. Not a lot of moving parts. I don't think the PTO's themselves will be very exciting. But if there is a PTO, then there is a pump!

Fraser:This means that there will be much more system/application troubleshooting that is happening. Whole trucks are coming in and we are able to deal with a few problems in our shop. That's the beauty of on-highway truck applications: they can drive the vehicle to us.

Tomas: Whole trucks, that sounds like it could make an interesting troubleshooting video--is that how it typically works? Or would we just add a PTO to our test stand to simulate a mobile application?

Fraser: PTO's mount onto a transmission. They are very simple devices. If we are troubleshooting one then it almost certainly is having the truck come in so we can inspect the whole system.

Tomas: What are the differences among the PTO units that Chelsea offers?

Fraser: Best to start right here: https://www.parker.com/content/dam/parker/msg/chelsea-products-division/home/Understanding%20PTOs.pdf

Tomas: With so many variations, how would I know where to start if I were looking to add or replace a PTO on my truck?

Fraser: If you are replacing then you would reorder what is already on there. Most assemblies such as pumps, motors, valves, PTO's have a tag on them with a part number.For new applications they determine a PTO by the space available, type of connection, type of transmission, type of pump, and any features they need.

Tomas: Can you use a PTO on automatic and manual transmissions?

Fraser: Yes

Tomas: Regarding servicing and testing PTOs, is that something that will be done in St. Catharine's?

Fraser: Not a lot of service is done on them. There is no testing: you need a suitable transmission to bolt it onto. These are not as complex devices as hydraulic pumps and motors