Fowler Associates Labs

Static Shocks on Treadmills
June 30, 2010
Steve Fowler Fowler Associates, Inc.

"I've recently purchased a Brand new treadmill and I've used it in the last 4-5 days with no problems. But today when I went on to start my workout and started the machine, as soon as I touched the heart rate control (metal) handle in front of the treadmill, an electric shock caught my hand. I tried several times and the same happened!! The shock only happens once I'm on the rubber platform of the treadmill."

"One thing I hate about treadmills at our club is the amount static charge you can build up when running on the treadmill!
When I touch the heart rate monitor it discharges like lightning!
When I use my ear buds on the TV monitor selection gadget. The charge releases itself about every 10 to 5 min. While running right in both ears!!!"

These are but a couple of comments from treadmill users that have been posted about static electric shocks. Look over the links on the bottom of this page for more information on the problem.

Sadly the "help" that comes from responses on the blogs are not very useful or accurate.

The problem is simple:

1. The problem is Triboelectric static generation

2. This static generation is from the insulative shoes walking on an insulative moving belt.

3. This electrostatic charge is accumulated on the shoes of the person inducing a high electric potential on the person. This means the person rises in potential (Volts) sympathetically to the accumulated charges on the shoes.

4. This potential causes a painful or annoying spark discharge when the person touches the grounded treadmill frame, heart monitor or an IPODs being used. It is like walking across a carpet and touching a metal door knob. ZAP! Except in this case the person is walking constantly and generating a constant charge ready to discharge each time the person touches metal.

Lack of grounding of the treadmill is not the problem. In fact it is the grounding of the treadmill that makes the energy of the discharge higher. It has a very low resistive path to ground of the discharge from the person. However, ungrounding the treadmill (don't do that) would not change the discharge much at all.

This problem can be reduced by the treadmill manufacturer by making the moving belt conductive with carbon loading or conductive fibers. Many manufacturers either do not know this or do not want to add the costs.

The problem can also be solved by connecting the person to the treadmill by an electrical wire (don't do this). However, this would make an electrical hazard and a physical hazard problem.

One solution which has had some very good success is the use of conductive threads in a bracelet form much like a "Friendship Bracelet". This bracelet's fine conductive threads perform what is called Corona Ionization. Corona ionization causes ions to flow from the charged person to ground (treadmill) and discharge the person so gently that they do not know it is happening.

These threads have very small points which allow ions to flow freely as soon as the person reaches a high potential from the triboelectric charging from the treadmill.

This animation shows how the bracelets are worn. As the person walks and reaches for the grounded treadmill metal parts or an IPOD, she is discharged gently by the passive ionization bracelet.

Click on the following video for a more detailed view. Bracelet Video

The following video shows how the bracelet works by Passive Corona Ionization. Notice the Van De Graff generator charges and arcs repeatedly until the bracelet is held close to it. The arcs cease during the time the bracelet is near the dome. This is because it is drawing ions from the Van de Graff by corona ionization unfelt by the wearer. It seems like magic but in fact it is real physics.

Van de Graff and Static Friendship Bracelet: click here

The bracelet can be fabricated using Static String* or any highly conductive threads.

Anyone can make such a bracelet if they have highly conductive string such as from Static Stop

To place an order for a bracelet, please contact Anit Static Bracelets & Accessories @
www. antistaticbracelets.com

Additional Links on the Topic:
From: Yahoo Answers
From: Horizon Fitness
From: Runner's World
From: Runango Running Forum
From: Epinions

* Static String is a trademark of Stop Static

**"Static Friendship Bracelet" is a trademark of the ESD Journal and Fowler Associates, Inc. Patent Pending