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  • Writer's pictureSusanne Nordman

Electromagnetic Chuck & Control Failure

When machining or finishing parts and raw materials, workholding along with its electrical controller are critical components of the machining process. If the part or material is not held safely, operator safety and equipment failure are inevitable.

To avoid unnecessary safety risks and downtime it is crucial to know how your electromagnetic chuck and controller work together and what to do when one or either of them should fail.

electromagnetic chuck rectifier

Electromagnetism is defined simply by Merriam-Webster as magnetism developed by a current of electricity. In the industrial world of workholding, the electromagnetic chuck provides the magnetism when supplied with a current of electricity from a controller.

Technically this type of electrical controller is a rectifier. All electromagnetic chucks are for operation from a direct current source. Because most factories have alternating current (AC) readily available, a rectifier system is used to convert the alternating current electricity to direct current.

A switch of ample capacity is also required to permit turning the chuck on and off. To minimize residual magnetism, the chuck control switch must also be capable of reversing the DC input to the chuck.

An important point to make is that many people confuse the releasing of the part or material as a function of the magnet not the rectifier when, in reality, it is the rectifier that controls that function.

Now that we have covered the basics of the physics of electromagnetism in the workholding industry, let’s get back to why your workholding and/or your controller has failed and what to do about it. 

digital multimeter
A digital multimeter may help determine the cause of the equipment failure.

It’s important to determine the cause of the failure to insure proper repair and or replacement of the workholding and rectifier. Many common problems with most electromagnetic chucks are discussed here. Keep in mind that most electromagnetic chucks can be repaired which shortens downtime compared to replacement with new.

Troubleshooting the controller or rectifier can be a little trickier. At one time, chuck controllers were designed and assembled by many companies, and it was usually best to go to the original manufacturer of the controller when needing assistance.

But with the closure of Magna-Flux International in 2021 and Electro-Matic’s chuck control division in Chicago, IL in 2023, many equipment owners have been left without help for those brands. If you have one of these brands of controllers, don’t despair!  Help is still available.

Magna-Flux International controllers were designed by the same individual that originally designed Magna-Lock USA FluxMaster chuck controls. You can read more about their relationship here, but Magna-Lock USA technicians should be able to troubleshoot either model. Electro-Matic controllers may still be serviceable by trained electricians as well, but spare part availability may be limited.

Magna-Lock USA provides an industry leading two-year warranty on their new FluxMaster chuck controls and phone support for the lifetime of the product. They are “plug and play” units that are shipped fully assembled and ready to use.

All larger wattage capacity FluxMaster models have an isolation transformer included with them. An isolation type transformer will provide galvanic isolation resulting in no conductive path present between the source and the load. This type of isolation is essential to protect against electrical shocks and to transfer power between the two circuits (rectifier and chuck) that should not be directly connected.

Magna-Lock USA logo

To learn more about Magna-Lock USA Fluxmaster chuck controllers, consider downloading our Comprehensive Guide to Flux Master Chuck Controls from our website. For assistance with your electromagnetic and chuck control failures or malfunctions, email us at or phone for technical support at 815-962-8700

ObsidianMfg Logo with brands

Obsidian Manufacturing Industries, Inc. is a Rockford, Ill. manufacturing company and is the OEM for Magna-Lock USA workholding, MagnaLift & Power-Grip lift magnets, and Arter Precision Grinding Machines as well providing surface grinding services. They are located at 5015 28th Ave. in Rockford, Ill. with a phone number of 815-962-8700. Check out more at

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