If you own, operate, or provide maintenance for equipment with motors using a variable frequency drive (VFD), you likely are aware of the problem of electrical arcing. It’s not a new or uncommon problem. Electrical arcing occurs when the voltage level gets too high and causes an ongoing electric discharge, which can damage your equipment and eventually cause it to fail.
In the December 2017 edition of Currents, the monthly publication for members of the Electrical Apparatus Service Association (EASA), there was an article by electrician Joe Junion titled “Motor Bearings: Electrical Damage Simplified.” In the article, Junion discusses how electrical arcing occurs in electric motors, and more importantly, what can be done to prevent or reduce the likelihood of damage to your equipment. Unfortunately, we can’t link directly to the article, because it is available for view only by EASA members. However, we will hit the high points of the article in this blog post and offer you Junion’s recommendations.
Junion says that to prevent electrical bearing damage caused by electrical arcing, it is often necessary to insulate the opposite drive end (ODE) of the motor. He offers three primary methods for doing so:
Purchase Insulated Bearings
Insulated bearings have a thin coating on both the outer and inner bearing races, which can provide some protection from electrical arcing. However, if the shaft voltage is too high, the insulation will not be sufficient to prevent bearing damage.
Add Insulation to Your Bearings
Another means of protecting your bearings from damage caused by electrical arcing is to install an insulating sleeve to the housing of the bearing. This will provide more of a barrier than what you will get on the insulated bearings mentioned above, but you will need to have access to a skilled mechanic who can complete the sometimes difficult installation process.
Purchase Ceramic Hybrid Ball Bearings
Junion says “…the absolute best means to insulate the ODE” is to use ceramic ball bearings because they “…provide the highest insulation available.” He also points out that they are “…a very durable bearing with a service life up to 10 times longer than a standard bearing.”
This article points out what we’ve been saying here at CBR for years—ceramic hybrid ball bearings are one of the best investments you can make in your equipment with industrial electric motors. It’s true that ceramic hybrid ball bearings come at a higher cost than standard bearings, but Junion correctly points out that the cost of ceramic bearings has come down substantially in recent years. In addition, the difference in cost between ceramic and standard bearings is almost always recouped when you don’t have to replace your motors’ bearings as often, and you see increased productivity due to reduced equipment downtime.
Contact CBR for Ceramic Hybrid Ball Bearings for Your Industrial Electric Motors
If you’ve been considering making the switch from standard steel ball bearings to ceramic hybrid ball bearings, but still have some questions, give us a call at CBR or contact us through our website. We are always happy to take the time to answer your questions or provide you with pricing on the specific bearings you need.