Newest Cat electric-drive truck continues to prove itself in the field
As the newest addition to the Cat® large mining truck lineup continues to rack up hours on mine sites around the world, Caterpillar is racking up feedback — and growing interest — from current and potential customers.
Several of the company’s mining truck experts shared some of that feedback — and talked about how the electric-drive Cat 794 AC is stacking up against the competition — during a webinar presented recently by the Caterpillar mining division.
The company’s first offering in the 290-tonne (320-ton) size class, the 794 AC has generated a lot of interest in the industry. “That size class has been very popular in mining, but Cat hasn’t been there before,” says Mark Richards, Caterpillar large mining truck commercial manager. “There’s been a lot of pull to have a Cat entry in that class. We’re seeing interest from across the world, from a variety of applications. We’ve run them in copper applications and coal applications. And the reception from mining customers has been fantastic.”
The chassis of the 794 is based on the Unit Rig truck line, which Caterpillar acquired as part of its purchase of Bucyrus in 2011. The electric drive system is the same system Caterpillar developed for its 795 AC electric drive truck.
Richards says the combination of design and expertise from two different entities takes this size class to the next level.
“The frame design itself on the 794 is extremely proven,” says Richards. “It has hundreds of thousands, if not millions, of hours. And then we’ve combined it with the 795 drive system, which also has over 4 million hours of proven performance. When you combine those two things together, you are seeing really the best of both worlds — and customers are responding.”
Accumulating high hours
As the 794 continues to work in the field, the truck’s engine and components have accumulated enough hours for the company to begin truly measuring their performance. Richards says the results are impressive.
The 794 is powered by the Cat C175-16 engine — the same engine Caterpillar uses in its 793 and 795 trucks. “The C175-16 really performs well, even in deep pit applications with very high load factors,” says Richards. “We’ve seen engines go well beyond 20,000 hours, and we expect even longer lives with lower horsepower settings.”
The electric drive components, used in both the 794 and 795 models, are also earning high marks. “We’re seeing a lot of field sites go beyond 30,000 hours, and we have pretty good line of sight to even exceeding our PCR (planned component replacement) targets in the field,” says John Hoffman, a senior project engineer for Cat large mining trucks.
Performing in unique applications
One of the first sites to begin using the Cat 794 is a unique coal application in Colombia. The mine has used Cat 793 trucks for overburden removal and 789 trucks for haulage, along with ultra-class trucks from another manufacturer.
“We’ve always seen that as a challenge,” says Richards. “We have wanted to go in there with our own larger, ultra-class truck and go head-to-head with the competition. And we’ve had that opportunity with the 794.”
The 794 fits in well in this mixed-fleet application, Richards says, running alongside other ultra-class trucks as well as the extensive Cat 793 fleet.
Richards describe the mine as an unusual application for a coal mine — one that provides a great proving ground for an ultra-class truck. “It has folded and dipping coal seams, so you actually have to chase those seams quite deep — quite different than a lot of the mines you’d see elsewhere. You actually see both types of applications, with longer, flatter hauls as well as the deep-pit type hauls.”
The 794 is uniquely qualified for this application, Richards says, because it offers three different power settings. For longer, flatter hauls, there’s the 2051 kW (2,750 hp) setting. Deep-pit applications would use the 2610 kW (3,500 hp) setting, while a middle setting of 2312 kW (3,100 hp) is ideal when both applications are present.
“Without doing an expensive change or swapping the entire engine like a lot of competitive trucks do, you can set that engine to various power settings to optimize your fuel and productivity,” Richards says.
Feedback on the truck overall has been good across the site, he says. “We’ve seen positive comments from the mine managers as well as the operators on the truck.”
Earning high marks
As 794 trucks are deployed around the world, Caterpillar and its customers conduct production studies to better gauge their performance. Hoffman has visited many of the sites and been involved in the studies and has found feedback to be very consistent.
He reports the 794 gets high marks in several areas:
- Empty machine weight. “Overall the customers are very impressed with our empty machine weight,” he says. “We’re typically coming in lighter than the competition, and that’s delivering more payload to them. They’ve been very happy with being able to truly hit the 290-tonne payload in most machine configurations — whether that’s having attachments on the truck or a liner package for the body. It has truly been able to deliver that payload, which is helping their bottom line.”
- Speed on grade. With a full Cat drive system and a Cat engine that are completely integrated, speed is fully optimized. “We’re getting more power to the ground,” Hoffman says. “I’ve actually seen in the field where the 794 has been able to catch the competitive trucks on the haul.”
- Maintenance. Hoffman says every mechanic he talks to is impressed with the ease of maintenance, thanks to two platforms that run on both sides of the engine, ground-level access to filters, and a large amount of space in which to work. “You’ve got your hydraulics on the left side of the truck and you’ve got your electrical on the right-hand side of the truck. It’s very easy and simple to maintain,” he says. “Some of the comments have been that’s it’s as easy as the competition, if not better in certain areas.”
- Braking. Even in wet conditions, the feedback from operators on the 794 has been positive. The 794 retarding capabilities are similar to the 795, with wet disc brakes and blending braking when coming to a complete stop.
Delivering a better bottom line
Caterpillar experts says the key benefits that customers are experiencing with the 794 are combining to deliver a better cost per ton.
“When you’re looking for a truck in this size class, really focus on what the numbers are actually saying. Focus on the machine weights and the payload, the speed on grade. Because that’s truly delivering a better cost per ton,” says Hoffman.
Richards agrees. “We went into mine sites where we’ve known we were going head-to-head with all of our top competitors. They had to have a truck that delivered the highest availability, the best Mean Time Between Stoppages (MTBS), the lowest Mean Time to Repair (MTTR), low maintenance requirements — in addition to all of the productivity features. We believe we’ve won in every case. Our customers are telling us that — and asking for this truck more and more often.”
“When you add it all up, we do believe this truck can deliver a better bottom line for our customers. And that’s really what we designed this truck to do.”