Empowering Motors began inviting people to Nominate an Industry Professional, and we’ve seen so many people nominate their peers- it’s truly inspiring! Today’s Motor Person of the Week is Patrick Hogg, Application Engineering Manager at Nidec Motor Corporation. In this interview below, Patrick shares some great info about load curves, service factor, VFDs, and sinewave power vs. pulse width modulation – in addition to telling us about how he got started in the industry.
Patrick: I started as an engineering co-op while I was finishing my undergrad at SIUE. I started working on PSC motors (permanent split capacitor) for dishwashers my sophomore year and was lucky to keep the position while going to school all the way through graduation. This was amazing because it gave me valuable experience needed to understand motor design, both electrically and mechanically, and this was really where my interest in electric motors and pumps began.
When I try to explain to my non-industry friends or acquaintances what it is I do for a living, I explain that I design and market electric motors for different applications. This usually then leads me into pointing out an electric motor, discussing pumping infrastructure, and expressing how much of their life is affected by electric motors. It is always surprising to me how many people do not understand how electric motors and the equipment they drive affects their everyday life.
Q. What is your favorite part of your job?
Patrick: My favorite part of my job is defiantly solving problems for customers. I receive application issues where customers are experiencing difficulties, and together we work through the problems to get them a product that solves an issue they had or allows them to put a new product into the market.
Q. What are you most proud of?
Patrick: Personally, I’m a proud Daddy to a perfect, little 1-year old daughter, and professionallty, I am most proud of receiving the Young Engineer of the Year Award from Hydraulic Institute back in 2015. HI has so many experts that have so much knowledge…it was amazing to receive such a prestigious award from a group of people I sincerely admire. In my job, I’m also pretty proud of some new vertical motor product lines I’ve released over the past couple years.
Q. What advice would you give to someone new to the industry?
Patrick: Dive in and get your hands dirty!! Get experience in anything you can – not just your field. Find out how marketing, operations, finance, and other business functions interact so that you can understand business and the market better. The more you know, the better you can react to enable you to create more valuable change more quickly. Above all, do not be afraid to ask questions. This helps you understand new things -questions unlock knowledge.
Q. Can you tell us about a cool project you worked on?
Patrick: One of the coolest projects I have worked on is the new product line that extended our TEFC Vertical motor line over double its current horsepower. It was fascinating to design and test parts that were some of the largest cast parts I had ever seen! We released the product, and it was the only full cast iron motor of its size and type. The amount of teamwork and time that went into the design was amazing. I came to understand multiple computer-aided software programs that we utilized to predict outcomes and then see it be tested so close to the prediction – it was simply astounding. This is a 20,000 lb. motor that we can predict outcomes within great tolerances. This was early in my career, so it really set the tone for all my other projects.
Q. What are the top 5 questions you get asked by your customers? How do you answer them?
1. Can you give me a XXHP motor? I love this question because this means a customer wants to work with us, but it is also one of the most frustrating because each installation and application has so many variables. Usually my response is to understand the application and environmental requirements. It is important to give as much information on application as possible to a motor manufacturer so that we can provide the motor that is the best fit. There are so many variations of an XX HP motor – some of them will work and some of them will not, so we must always ask questions to spec the correct motor.
2. Is this motor ok to run on a VFD? This question is much to the same point as the last one. It all depends. Most induction AC motors can “run” on a correctly sized VFD, meaning they will turn and operate, but the question is for how long can they reliably operate. Motors that are powered by VFDs require special considerations for protection of windings and bearings, as well as the installation of the motor and drive for maximum mitigation of damaging effects that could be caused by improper installation or operation. So the general answer could be ‘yes’, but the correct answer is “you need to check with your motor manufacturer and drive manufacturer with specific application requirements to make sure a motor can operate with a VFD reliably”. It is also best practice to have correct installation of a motor/drive system, which usually involves much more than is usually considered.
3. What is the difference between sinewave power and PWM (Pulse Width Modulation) power? Well, sinewave is the power waveform that is supplied directly from utilities and has a fairly regulated power quality at a single frequency (meaning it runs AC induction motors at a single speed). Sinewave power waveforms have a nice smooth sinewave oscillation with gradual rise and fall from one peak to the negative peak of the AC voltage.
PWM is the power waveform generated by the switching function of a VFD. This waveforms allows the drive to simulate a sinewave by pulsing full voltage on and off for different lengths of time. What this allows for is the drive to control the waveform for multiple reasons, but mostly to change the frequency and inherently change the speed at which the motor runs. This PWM waveform can have very fast voltage rise times or even voltage overshoots above the rated voltage. What this can cause if not installed correctly is large peak voltages as well as voltage differential on three phase systems. This requires motor manufactures to protect motor windings against these possible voltage spikes and differentials because we cannot guarantee the system will be installed correctly in the field. This is a $5 answer to a $500,000 question (::laughs::). Much more usually goes into this.
4. What does the ‘Service factor’ on the motor mean? The service factor is an indicator of a margin of safety designed into the motor so that if there is an instance where an anomaly happens in the driven equipment, the motor can run overloaded for a short period of time. Motor rated HP is the HP that the motor can continuously operate. The Service factor is a multiplier of that rated HP that the motor can handled in case of an operational issue within the system. Motors should not be run in the service factor for extended periods of time. Doing this will affect the life and reliability of the motor.
5. Why do you need the load curve of my equipment? The load curve of the driven equipment is a key indicator telling if a motor can successfully operate a piece of equipment. We can see the torque required by the equipment and compare that to the torque that the motor can generate. This evaluation tells us the amount of current the motor will draw, the heat rise generated from running the load, and if the motor can operate the equipment at reduced voltage. This load curve can also indicate on / off times of cycle loads and much more. One of the single most important pieces of information is the load torque curve.