Variable speed Control problem

If you've replaced the variable speed unit in your Bosch 11318EVS SDS-max Demolition Hammer and the variable speed is still not working, there could be a few potential reasons for this issue. Here are some steps you can take to troubleshoot and address the problem:

1. Check Wiring Connections: Ensure that all wiring connections related to the variable speed control are properly connected and secure. Loose or damaged wires can disrupt the variable speed function.
2. Control Switch: The control switch itself could be faulty. Test the switch to make sure it's functioning as intended. Use a multimeter to check for continuity across the switch terminals in different speed settings.
3. Speed Control Potentiometer: The potentiometer, which is responsible for adjusting the variable speed, could be malfunctioning. Test the potentiometer with a multimeter to ensure it's changing resistance smoothly as you adjust the speed.
4. Electronic Control Board: The issue could be with the electronic control board that governs the variable speed function. Inspect the board for any signs of damage, such as burnt components or solder joints.
5. Brushes and Carbon Motor Contacts: Worn brushes or carbon motor contacts can affect the motor's performance and, consequently, the variable speed control. Check the condition of the brushes and motor contacts and replace them if necessary.
6. Power Supply and Voltage: Ensure that the tool is receiving the correct power supply and voltage. Incorrect power supply can affect the tool's overall performance.
7. Manufacturer's Support: If you've exhausted your troubleshooting efforts and the variable speed is still not working, it's advisable to contact Bosch customer support or a professional tool technician. They can provide more specific guidance based on the model and diagnose the issue accurately.
8. Professional Repair: If the issue is complex or involves internal components, it might be best to seek the assistance of a professional tool repair technician who has experience with Bosch power tools.

Remember that working with power tools and electrical components carries inherent risks. If you're not comfortable or experienced with tool repairs, it's recommended to seek professional assistance to ensure safety and prevent further damage to the tool.

It's possible that the variable speed control may be the issue with your Delta 23-197 grinder. However, before attempting to bypass it, there are a few other things you can check.
First, make sure that the grinder is properly plugged in and that the power outlet is functioning correctly. Check the power cord and make sure that there are no cuts or breaks in the cord.
Next, check the switch and make sure that it is properly engaged. If the switch is faulty, it may need to be replaced.
You can also check the brushes on the motor to see if they are worn out or damaged. If the brushes are worn out, they will need to be replaced.
If none of these troubleshooting steps resolve the issue, it may be possible to bypass the variable speed control. However, this is not recommended unless you have experience with electrical wiring and understand the risks involved.
If you do decide to bypass the variable speed control, you will need to identify the wiring that controls the speed control and connect the wires together to bypass the control. However, keep in mind that this will result in the grinder running at full speed all the time and may shorten the life of the motor. It's always best to have a qualified electrician or technician perform any electrical modifications to your tools.

variable foot control==the farther you push it...the faster the machine goes....
non variable....only has stop...and run....

VFD is a device used for speed control of 3ph induction motors & automation process control

The Humming indicates the motor itself is going out. Its going to need a replacement soon.

Hi.

Depending on the make and model, and type of washer, you may need to test and eventually replace the following parts:


On top loads:


Variable speed motor .
Motor coupler.
Transmission.
Control board.
Motor control unit (if present)


On front load :


Variable speed motor .
Motor coupler.
Control board.
Motor control unit.


On top load the problem is often transmission or variable speed motor. On front load MCU or motor.

some manufacturer already attached a variable speed controller when you purchased them, meaning the unit requires this control, but in your case when you purchased it, it does not have any, meaning they sell it to the market as ready to use, so why install additional control?

There might be an installation error during the assembly, so all you have to do is just interchange the wire connected to the control from LOW, MEDIUM and HIGH, it is a trial and error thing but it won't affect or damage your unit, maybe your high speed connection was connected to a low speed control, so just inter-change it. Remove the variable speed control

Unfortunatly Dremel who is owned by Bosch has discontinued that tool and parts are no longer available.

You need to replace the variable speed control switch. Other than that, your not doing anything wrong. Have fun