|01-12-2009 10:19 AM|
Sewing machine sped
My motor runs all the time, very smooth and quiet-- but then i'm half deaf so that helps--half hp ac single phase. It must have a hell of a flywheel because it runs for 15 min. after you shut it off. I think my pfaff is the same number as yours but not sure would have to look as it is over to my kid's place now. Good luck.
|01-12-2009 08:01 AM|
There is a big difference in the different brands of servo motors. I researched quite a bit before settling on the SewQuiet 3000. I chose it because it gave me the most features and the most control of any that I looked at. It was not the cheapest, ($140 3 years ago) but it was not the most expensive either. I don't have a problem with the "steps" you talk about, but when you first start sewing, you have to be careful not to push too hard on the treadle too quickly or it will race for a few stitches. After that, it is as smooth as silk.
BTW, just not having to listen to my clutch motors running all day was worth switching to me!
|01-12-2009 07:39 AM|
I bought one of the early servomotors from Allbrands. At that time, they were only selling 1/4 hp motors, so that's what I got. I use it on my 111W155 and several other industrial sewing heads and have never had a problem with it being underpowered. When you consider that a home machine is somewhere in the 1/20 to 1/10 hp range, 1/4 hp is quite a step up and 3/4 hp is akin to dropping a Cadillac engine into an Escort.
One problem I have with my servomotor is that the speed changes are not smooth - there are about 5 "steps" from 0 to full speed and sometimes I want to sew in between two of the steps. I have never heard anyone else mention this, so perhaps it has been fixed in the later or more expensive models.
|01-11-2009 09:48 PM|
The servo is a DC motor (same principle as a variable speed drill) and is only on when you press on the treadle, so you won't even hear it unless you are sewing. I can adjust my servos so that if I want to, pushing down on the treadle all the way will only make one very slow stitch at a time, but I have the same power as if the motor was going full speed. My motors are Reliable SewQuiet 3000's.
BTW, speed and power are two different things. With regular AC motors, a 1 hp motor produces 3 ft. lbs. of torque at 1750 rpms. A 1/2 hp AC motor produces 1.5 ft. lbs. of torque at that speed. As you go slower, torque increases. If you go above 1750 rpms, torque will decrease.
Servos are DC and have constant torque throughout the speed range.
|01-11-2009 09:22 PM|
|jcarter||This one is the standard single speed clutch motor that all beginner's seem to have trouble with.You can slip the clutch and "vary" the speed somewhat between 0 and to fast, but it is so sensitive that it is impossible to slow it to the point that you can see the needle instead of a blur.Once the clutch locks up it is full speed, no ajustments. Gringo, I don't know what you have, sounds like it is set up more like a servo motor.What model of a Pfaff do you have? Jim.|
|01-11-2009 07:36 PM|
After reading Dan's letter, I had to go look at my machine. My motor is a clutch type (it says easy clutch) and it has variable speed from one stitch at a time to probably 200 mph. We have three machines and all have the same type motors. 2 Chandlers and a Pfaff. The only ones I've seen that are single speed are the old leather machines from the shoe shops and they are really slow. If it only has one speed you are going to want to change it for sure, you need variable speeds. Just push pedal down by hand an see if it speeds up as you push down.
|01-11-2009 07:36 PM|
|jcarter||Thanks Dan for the good explanation.I didn't realize that you had servo motors on your machines.I see that I don't have to be concerned about a 1/2 servo not being as strong as a 1/2 clutch style.Changing the pulley would be an option, but will still be to fast at even half speed,and you would still have to get used to the clutch.Don't think I have enough spare time to practice to get good enough to work on the real thing.It sounds like the servo will give us the control that a beginner needs to play around and have fun. Thanks Jim.|
|01-11-2009 06:09 PM|
You hook the treadle (foot pedal) up to a servo motor just like you do a clutch motor. No, your servo motor does not need to be more powerful than a clutch motor. I replaced 1/2 H.P. clutch motors with 1/2 H.P. servo motors on both of my industrial machines. They work beautifully, and I sew every day for a living. I've been sewing for almost 35 years, and I can't tell the difference.
A servo motor is a constant torque device, so you will get the same amount of power throughout the speed range of the servo. What is the difference between a clutch motor and a servo? The servo theoretically will have less power at slower speeds than a clutch motor, but a servo will have more power at higher speeds. What does this mean for average sewing? You won't be able to tell the difference. The problem with a clutch motor is that it is either on or off. Unless you are willing to spend enough time to be comfortable with the machine, you will still have accidents and screw something up. The servo motor gives you the option of having true variable speed control over the motor immediately. In other words, the less you press on the foot pedal (treadle) the slower the servo will go. The clutch motor is always going at its base speed, usually 1750 RPMs, and you need to slip the clutch to be able to sew slower. This takes a LOT of practice to do it consistently and effectively.
If you want to slow down your clutch motor, you have two options. You can possibly have an electrician re-connect the wiring in your motor down to 875 RPMs, ( depending on the motor) or you can replace the pulley on the clutch motor with one of smaller diameter, or both. If you reduce the RPM of the clutch motor by 1/2 through a pulley on the clutch motor 1/2 the diameter it is now, you will go 1/2 as fast as you do now. The same is true of re-wiring the motor. If you reduce the RPM by 1/2, you will go 1/2 as fast as you do now. If you reduce the pulley diameter on the clutch motor by 1/2, and reduce the RPM of the motor by 1/2 as well, the clutch motor will run at 1/2 of 1/2 of its full speed, or 1/4th the speed it runs at now. Now the bad news........you can do all of this and STILL not slow it down enough to where you are comfortable sewing. A servo motor eliminates that problem. Servo motors are the perfect choice for novice sewers. You can sew as slowly as you want at first and then speed up if you want to. This is not the case with a clutch motor.
|01-11-2009 02:45 PM|
Sewing machine sped
You should be able to adjust the pedal to go slow enough. I had same problem years ago. The main thing is getting use to pushing the pedal which will come with practice. The easiest way is to put a piece of wood or some type of stop under front of pedal. Push down until you find a speed you are comfortable with and adjust your stop accordingly. When you find the right speed you adjust the rod that goes to clutch arm. The rod should be adjustable up and down and also try it in different holes in clutch arm. Leave the spring alone. These are good motors and should last forever. Hope this helps some.
|01-11-2009 12:50 PM|
Servo motor versus Clutch motor questions?
We finally got ourselves a used sewing machine this week.It is an older Phaff 145 h-3 that hasn't seen a lot of steady usage, so is in real good condition. With the clutch motor, it goes way fast for me to accuratley see what I'm trying to sew, and my wife can't control it very well either, compared to her home machines. We have played with pedal height and spring tension, but can't let it slip to go slow consistantly to get comfortable with it. We are looking at getting a servo motor for it.When you look at the servo motor option on the Tacsew site, they sell a 3/4 horsepower servo to replace the 1/2 clutch motor!! Do you need the extra power in a servo? Or is a 1/2 servo as good as a1/2 clutch style? What do you hook the pedal lever up to on the servo motor?Can you set or adjust the top speed with the servo so that say setting #1 would be a quarter of top speed,with the pedal pushed right down, and setting or adjustment#2 might be half of top speed pushed right down? Any explanation of how the servo motor works or controls would be great. Thanks Jim.