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Armature Braking Saves Brush Wear - by Bob Thomas
Many different types of brake washers have been used in starter motors (see Figure 1). Those found in older starters often played an important role in minimizing end play, which was explained in detail in last month’s issue. However, the primary job of a brake washer is indicated in the name. Brake washers stop the armature to prevent excessive coasting after engine start up when power is removed from the motor. They are the armature’s only brake. As such, they play a very important part in the life expectancy of any starter, because most brush wear takes place after current is removed. ...
Aside from the construction and content of the brush material itself, the rate of brush wear is affected primarily by two factors: spring pressure and current flow. It makes sense that high spring pressure increases friction between the brush and the commutator, and we know that friction causes wear. But when current is flowing, the level of friction is significantly reduced, and arcing comes into play. That is because current flow reduces friction, but it creates arcing. Coincidentally, arcing can be reduced by increasing the spring pressure. This is the dilemma faced by all DC motor designers. The balance between spring pressure and current flow is a delicate one that must be engineered into each starter. Brush content and construction play a big part in that balance, too, but that will be discussed in detail in a future edition. For now, just be aware ...
The Benefits of Attending a Trade Show - by Sherri Powers
Trade shows present the ideal environment in which vendors compete for your business. Every exhibitor there is interested in having you as a customer. As you walk around, you can immediately compare numerous suppliers’ parts, prices, and services. This is also the ideal place for you to discover new suppliers you never knew about.
By attending a trade show, you can figure out which suppliers sell what you are looking for, and which solutions are the best for you—all in just one day. Trade shows can also provide you with greater confidence in your purchase. Being at a trade show gives you the ability to see parts firsthand and actually touch and work with various products before you buy them.
While attending shows is great for product comparison and a hands-on experience, simply attending a trade show can be daunting and often leaves some attendees unsure of what to do. To get the most out of your experience you need to be proactive and prepared for what will be coming at you. Here are a few suggestions:
Have a clear idea of what you are looking for. Do a little bit of research before you show up and have a basic understanding of what you are looking for. Come up with a list of things you NEED and a list of WANTS that would be nice to have. The lists you make should be a guide, but be prepared to be a little flexible. There will be new products out there that you are unaware of right now. Take samples of parts that you cannot find or may have had trouble with. Share your ideas and suggestions so that suppliers can do a better job in satisfying your needs.
Take extra business cards with you. A lot of exhibitors and attendees use business cards to keep track of who they’ve talked to. Estimate how many cards you think ...
Denso F-Series 4kW Starter - by Bob Thomas and Wes Grueninger, Sr.
The straight drive 4kW Denso F-Series diesel starter was introduced in the late 1970s as a direct replacement for the aging Delco 35MT (see Figure 1). This starter has been giving some rebuilders headaches ever since, by staying engaged on the vehicle following engine start, even though it operates properly on a bench test. This series starter was used on various Caterpillar, Onan, Hino, Mercruiser and most prominently John Deere applications with 10 different Lester numbers covering this design in 12 volts.
One of the peculiarities of this starter is a soft-engagement feature that is achieved by rotating the armature at reduced speed during solenoid pull-in. This helps to eliminate the possibility of the pinion milling the flywheel when abutment occurs. However, this feature has also contributed toward making the rebuilding of this starter more of a challenge.
Most starters accomplish a smooth engagement by grounding the solenoid’s pull-in coil through the motor terminal. During pull-in, current that is limited by the solenoid’s pull-in coil flows through the motor to create a very slow rotation of the armature and pinion during pull in. While this works well for gas engine applications, flywheel milling has long been a consequence when the initial ...
Dual Output 10DN Alternators—Lestek to Balmar - by Bob Thomas
The Delco-Remy 10DN was General Motor’s first mass produced automotive alternator. This stoutly-built, externally regulated, B-circuit alternator was used in passenger cars, pickup trucks, farm tractors and industrial equipment from 1963 to 1971. The basic design has lived on for decades in the form of high output specialty alternators from Lestek, Powerline, Pentex and Balmar. Some of these were dual-output alternators.
Because the 10DN design was both reliable and versatile, many of those alternators are still in use today. Typically, they use heavy duty 50 or 70 amp, 1/2-inch press-fit diodes, with braided leads connected to the stator terminals. Whenever you encounter one of these for rebuilding, the biggest difficulty is getting good connections between the diode stems and the stator terminals.
Kits are available that come with dual braided leads, and they work well when you have only six diodes to replace.
But the dual output alternators typically have nine diodes, three negative and six positive, because there are two positive heat sinks. This setup eliminates the need for a battery isolator, but it poses some challenges when it comes to rebuilding it. Flexible connection straps are required to supply ...
GM Duramax Engine—Cranking Problems Caused By Bad Ground Inside Starter Motor - by Bob Thomas
When General Motors introduced the new Duramax diesel engine in 2001, they opted to crank it with a Hitachi starter rather than a Remy, which surprised many people in the rebuilding industry. The new engine was produced by DMAX Ltd, a joint venture between GM and Isuzu. The 6.6 liter turbo-charged V-8 engine was the first high-pressure, common-rail, direct- injection diesel to be used in the US vehicle market. Dodge and Ford eventually followed GM, but it was years later.
The S14-101 Hitachi starter (see Figure 1) is a conventional offset-gear reduction cranking motor rated at 2.2kW. The decision to use it on the Duramax engine was probably a result of influence from Isuzu. Weight or limited space prevented the use of the longer and heavier 28MT. As of November 2012, over 1.5 million of these engines have been produced, and most are still on the road today. Through 2013, there were three versions of this Hitachi starter, the latest one using a shorter solenoid. The original starter number’s 101 suffix was followed by 101A, 101B, 101C and 101D.
One common problem seen in all versions of this starter has been a poor ground connection, similar to that seen in many other starters with bimetal connections in the ground path. The ground we are referring to here is ...
Plain Talk: Gonna Take More Than Just “Doing It”! - by Rob Buksar
This September 17th will be one year since I was hauled off to the ER by ambulance ... a time and circumstance that changed my life forever!
During a recent moment of frustration, I was talking to my sister on the phone. I expressed how rattled I’ve become, because I figured by this time, everything around me would have totally returned and resumed to as it was prior to my being hospitalized. Wrong!
My sister painfully reminded me that, when I was transported to the ER, I was moments away from a body bag. I was that close! In light of the fact that I’m no kid, my recovery has been remarkable for a senior citizen, at least so I’m told! Nevertheless, I have my life, and I’d better get used to the fact that, starting with me, everything has changed relationships, business, climate, environment, etc. It’s all different!
It’s quite the eye-opener, returning to the game after being benched for a while. Believe me, one gets a real different perspective sitting in the bleachers instead of being in the middle of the game. When you’re a small guy, chances are you are a principal player in the business. Every day is another day of ...
Powerline Brush-Holder Ground Problem - by Bob Thomas
Several high-output alternator manufacturers, including Powerline and Pentex, have used the externally regulated 100-amp Ford alternator from the 1980s as a base platform. These alternators may look similar to the original Ford unit, but actually, every part has been modified. Recently we worked on a Powerline alternator that charged erratically on the test bench. When it was not charging, we noticed that it had no field draw. Applying pressure to the brush holder plug in different directions seemed to make it start charging again.
What we suspected and we found was a poor negative brush connection (see Figure 1), evidenced by arcing under the brush-holder ground screw. This is a common problem with these alternators. We also discovered that the last person to rebuild this alternator had used a standard Ford brush holder, which fit perfectly into the modified slip-ring end housing.
However, the standard brush holder does not hold up to the heat and vibrations created by a high output alternator when it is mounted on a diesel engine in the cramped engine compartment of a van-bodied conversion bus. The plastic which is used to make the standard brush holder for automotive applications is not the same material that Powerline used for its original brush holder. In this case, standard Ford brush holder fatigued, ...
“The Usual Suspects”—Blaming Voltage Regulators - by Bob Thomas
“It must be a bad voltage regulator.” How I wish I had a dollar for every time I heard those seven words. Since they were invented, voltage regulators have been taking most of the blame for charging system malfunctions. Guilty or not, they have often been replaced and discarded. Sometimes, when that failed to correct the problem, they have even been replaced again.
I have had customers specifically request that I replace their voltage regulator, because a friend, relative or neighbor told them that it was causing all of their electrical troubles. I have also heard that the parts store has tested “this” alternator and proclaimed that it definitely had a bad regulator. How could anyone possibly know that? Overcharging, undercharging or not charging at all—there are always other things that could cause those malfunctions besides the voltage regulator. Yet, definitively, the parts store employee standing next to a computerized test bench or the neighbor who has been “fixing” cars since he was in high school, announces that the voltage regulator is bad. How can anyone argue against that?
Not long ago, I talked to someone who said that he had replaced a regulator three times, and the alternator was still not working. When I asked him why he kept changing the regulator, he told me “Every other part tested good.” When I asked if he tested the voltage regulator, he said “No”. When I asked why, he said, “I figured it had to be a bad ...
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