The Neon 21 tension head is the electronic tension head, which makes stringing much faster and easier:

• It has the microcontroller chip to control and monitor the tension; it provides 1 pound tension accuracy
• Easy to calibrate the electronic tension head.
• The two-way DC motor to pull and release the string. You do not have to use muscle to operate. You just need to push the button to pull and release the string.
• The voltage deviation of the local AC power line has no affection on every tension pull.
• Fuse protection
• LED tension readout to display the tension setting
• Pound/kilogram selection switch to select the pound or kilogram operation
• Precise tension on every pull
• All-metal diamond-coated string gripper
• 2 years warranty on the electronic tension head
• The characteristics of the electronic tension head are constant pull and precise tension on every pull.

The Silent Partner tension head is the electric tension head:

1999 to 2001 model:

• The Silent Partner uses the 1977 General Electric AC motor speed control circuitry. This circuitry is used to control the speed of the AC motor, not the torque of the motor. Therefore, the tension is varied on every motor pull. The tension deviation is about 5 - 10 pounds on every pull. When the AC motor gets warm, it lowers tension.
• Can not calibrate the electric tension head. There is no way to calibrate the tension head.
• The AC motor only turns clockwise; can not turn counterclockwise. Therefore, The string gripper can only be able to pull the string, it can not release the string. You have to use the hand to re-wind the string gripper counterclockwise to release the string. you need to use muscle to re-wind the string gripper.
• The voltage deviation of the local AC power line affects the AC motor turns. Therefore, the AC voltage deviation affects every tension pull.
• No fuse protection
• No LED tension readout
• Only has pound selection switch
• Varied tension on every pull
• Plastic string gripper
• 1 year warranty on the electric tension head
• The disadvantage of not having two-way DC motor and LED tension readout is: varied tension on every pull, not easy to release the string, no way to calibrate, and time consuming.

Present model:

• The Silent Partner latest electric tension head uses a toggle switch and an AC motor with 2 coils. See attached diagram of this electric tension head. (The previous model has an AC motor with single coil. While the coil energized, the motor can only turn clockwise; it can not turn counterclockwise.) With 2 coils, the benefit is: when the toggle switch flippes to the right, the primary coil is energized. It will turn the AC motor clockwise. When the toggle switch flippes to the left, the second coil is energized. It will turn the AC motor counterclockwise. This approach solves the string gripper re-winding issue. But it still uses the General Electric AC motor speed control circuitry. For the performance, see the test report by a professional stringer.
• No fuse protection
• No LED tension readout
• Only has pound selection switch
• Plastic string gripper
• 1 year warranty on the electric tension head

The Silent Partner’s electric tensioner design (U.S. Patent No. 6,162,139) just uses the General Electric universal motor-speed control circuitry. Refer to the Figure 12-18 of the 1993 Small Electric Motors textbook.

Table 1 illustrates the comparison between the Silent Partner’s String Tensioning Device and the General Electric universal motor-speed control circuitry.

1. The Silent Partner just changes the values of the capacitors and resistors from this General Electric universal motor-speed control circuitry. The Silent Partner even uses the identical reference designation, such as R1, C1, R2, C2. The Silent Partner uses the Quadrac as the control device in his Figure 2 of U.S. Patent No. 6,162,139. One Quadrac is equal to one Diac and one Triac. Therefore, the Silent Partner just uses the General Electric universal motor-speed control circuitry.
2. The Silent Partner just uses the General Electric universal motor-speed control circuitry, which is public knowledge.
3. The Triac website of the Triac manufacturer "Teccor Electronics" indicates that typical applications include motor speed controls, heater controls and incandescent light controls.
4. The application notes AN1003 of the Triac manufacturer "Teccor Electronics" provides the explanation of the Diac-Traiac phase control. Also it indicates that several speed control and light dimming (phase) control circuits have been presented in this application notes.
5. For complete information of the Silent Partner’s electric tensioner (U.S. Patent No. 6,162,139), please view the website of the United States Patent and Trademark Office.

A professional stringer, Thomas E. Ruddy, tests a Silent Partner 2002 e.stringer.

Tenion pulled to correct tension most of the time, but lost more # than I thought it should. When tension pulled not enough stable or constant pulled to have a even racket strung. I have strung for the US Davis Cup team. I have also strung for school districts in and out California, Montebello, Whittier, San Jose, San Luis Obispo, San Diego, New York Germantown middle school district. Also US badminton team 84-88, 92 Olympic teams, to present 2002.

Test By Thomas E. Ruddy
Date: 10-13-02

If you have the Silent Partner e.Stringer, please let us know how is your e.Stringer performance.

Silent Partner's FAQ#4:

4)    Are all electronic machines based on the same technology?

Important differences distinguish the technologies used in various electronic machines. There are three types of technologies. The first consists of electronics for direct torque control of a motor so that the motor cannot pull more than the desired tension. Silent Partner holds a patent for this technology (US Patent #6,162,139) and offers it exclusively on the e.Stringer, the e.Stringer CL and the e.Stringer FL, as well as in retrofit tensioners for other brands of machines. The second type of electronic technology consists of a motor control linked mechanically to a pre-loaded spring. Tension adjustment is effected by turning a knob that compresses the spring to the desired tension so that a limit switch is tripped and the motor is stopped when the tension is reached. This type of control, which is identified by a tension control knob located to the right of the machine (see picture), does not provide constant pull because tension has to drop by more than 15 lbs. for the limit switch to turn the motor on again, and this does not normally happen during stringing...

A professional stringer, Thomas E. Ruddy, tests a Silent Partner 2002 e.stringer.

Tenion pulled to correct tension most of the time, but lost more # than I thought it should. When tension pulled not enough stable or constant pulled to have a even racket strung. I have strung for the US Davis Cup team. I have also strung for school districts in and out California, Montebello, Whittier, San Jose, San Luis Obispo, San Diego, New York Germantown middle school district. Also US badminton team 84-88, 92 Olympic teams, to present 2002.

Test By Thomas E. Ruddy
Date: 10-13-02

Refer to the complete test report.