Foot Control Sewing Machine | Foot Controls | Foot Pedal | Sewing Machine Rheostat

The foot control is like the accelerator pedal of your car and controls the speed of your machine. There are two types of foot controls on the market. One is electronic and has circuitry inside it. The other is a rheostat. It can be good to understand the difference. Note: It is important to know that some foot controls are designed to work only with their own sewing machines. These machines may provide special features, such as raising and lowering the needle or presser foot. Some may engage the thread cutter and lift the foot. Others may be programmable and allow the sewist to choose what features they engage. These foot controls should always be replaced with the exact same one. 

This type of controller has one or two tubes with a number of small carbon wafers in them. When you step on the pedal, you introduce current to the wafers. As you push down harder, these wafers compress together and are able to conduct more electricity, thereby increasing power to the motor and increasing speed. Inside of rheostat foot control The main issue with this style is heat buildup at slow speed. When you use light pressure on the pedal, the carbon wafers are not compressed together tightly, leaving space in between.
Electricity arcs across these spaces and creates heat. You can sometimes hear these little sparks. You will probably feel the heat. There is no danger; it’s just how they are designed. If you shake one of these controls and hear something rattling around or see a piece of a wafer falling out, I would replace it. If it gets extremely hot, I would also get rid of it.
Another issue is getting only high speed as the control gets older. This can be because the metal contacts are burned or carbon wafers have disintegrated. Sometimes this condition can be fixed by a sewing machine technician. When the time comes to do this, you might consider replacement with an electronic foot control. 

In this style of control, the carbon wafers are replaced by electronic circuitry. This is simple circuitry designed to provide smooth and even power to the motor at all speeds without arcing and heat. They are very inexpensive and make a great replacement for that old rheostat when it gives up. Some of these circuit boards have a fine adjustment for setting slow speed.

Erratic Speed
Occasionally the electronic foot control can give an uneven speed. This is especially true if you like to sew at a certain speed. If this happens, unplug the control and press it up and down through its entire range of motion for a minute. This removes grease and debris from the resistor and often solves the problem. Early versions of electronic controllers, starting from the 1970s, may no longer provide control at slow speed. These have a very inexpensive capacitor that can be replaced to solve the problem. A knowledgeable sewing machine technician will be aware of this. 

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