kwalk20 Report post Posted November 28, 2015 (edited) Hi all! I need some help here. I'm totally new to industrial sewing machines, but I ended up getting a Seiko sth 8bld-3 with a Family Sew 550s servo motor. I don't know if this is normal, but I don't believe so. Since I'm new I want to sew at a slow speed 350, but the machine keeps stopping. I have to continuously pull the handwheel to get it back moving and sometimes it's really stiff. It starts back sewing, but I can only get a few stitches in and it completely stops again right in the middle. Pull the handwheel, get only a few stitches in and it stops cold again. Sewing in the 600 range is moving too fast and I can't control it as well, but it doesn't keep shutting off. Someone thought maybe it has a short in the motor? Any advice? This is getting on my nerves and it's too cumbersome to have to pull the wheel all the time. I have seen a vid where (Mr.colt?) makes his practically walk in 350 and mine won't do that at all. Any help out there? Thanks in advance!! Edited November 28, 2015 by kwalk20 Quote Share this post Link to post Share on other sites
Wishful Report post Posted November 28, 2015 Some servo motors lose their muscle and cannot punch through very well so a speed reducer will usually correct that. Does the problem occur with thinner material/leather? Quote Share this post Link to post Share on other sites
SARK9 Report post Posted November 28, 2015 All brush-type motors eventually wear out the brushes or load up/groove the commutator. If the little spark-and-ozone generator has seen a lot of service, its something to look at. Frequently you can simply adjust the brushes in for a bit more tension and get more use out of them. They shouldn't be expensive if they need replacing. -DC Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted November 28, 2015 Do an experiment to see if the motor is defective. Loosen the motor adjuster nuts and speed reducer until you are able to remover the belt from the motor. Set the dial to the slowest speed. Start applying pedal until it starts running. Does it come on gradually, very slow at first? Or, does it jerk on at a running rpm? Move the speed pedal all the way toe down, then let go. Does the motor cut out as the pedal moves, when it is supposed to be spinning? If it jerks on at the running speed, it is misaligned at the factory. If it cuts out as you try to change speed, it is defective. If it starts gradually, but lacks enough power to run the machine slowly at the 350 setting, you will either need a smaller motor pulley or a 3:1 speed reducer, if you don't already have one installed. Contact the dealer you bought the machine from about exchanging the motor, or getting a smaller pulley or speed reducer kit. Quote Share this post Link to post Share on other sites
kwalk20 Report post Posted November 29, 2015 Thank you for the responses guys! Wishful, it behaves the same way on any thickness, light to heavier. Sark9, it's a brand new unit so there shouldn't be any wear. I will get the hubster to check the brushes. I believe it came with extra. Wizcraft, I'm going to do your test protocol right now. How would I know if it has the 3:1 speed reducer? Is it built in? Quote Share this post Link to post Share on other sites
kwalk20 Report post Posted November 29, 2015 I did the test and it jerks on. Question, is this motor supposed to keep spinning a bit after releasing the pedal (inertia)? If so mine does a dead stop as soon as the pedal is lifted. Quote Share this post Link to post Share on other sites
Colt W Knight Report post Posted November 29, 2015 With he belt on, mine stops. Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted November 29, 2015 I did the test and it jerks on. Question, is this motor supposed to keep spinning a bit after releasing the pedal (inertia)? If so mine does a dead stop as soon as the pedal is lifted. It should not jerk on. Something is wrong with it. These motors have a cork brake that locks the motor when the actuator lever is all the way up. The brake can be adjusted a little for more free play. It requires opening the end of the casing to access the lever and brake pad. You asked about how to know if you have a speed reducer. It is an external device with three pulleys fused together. They are 2", 6" and 9" in diameter. It would be bolted under the table, along side of the belt slot. Quote Share this post Link to post Share on other sites
kwalk20 Report post Posted November 30, 2015 Thank you Wizcrafts! I'm not sure if my cork brake is installed then. Maybe they didn't put it on. I couldn't figure out what it was as it was in the extras baggy. If it's not installed would that cause the problems I'm having? We are going to look to see if there is one on it and if so this one is an extra. Colt Knight, your vid was the one I was referring to up post. Mine is unable to "walk" as your did. Did you install a smaller pulley or is that the one that came on it? Also, in the vid it looks like you are fine tuning the dial. Mine only clicks from one setting to the next and cannot dial in between. I click to 350, click to 660 and so on. Am I correct in that your dial can fine tune in between the speed settings? Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted November 30, 2015 There is a spare cork brake in the bag of accessories. There is always one pre-installed. If you remove the brake cork, the motor will not stop on its own until it runs out of inertia. You would have to use your hand on the flywheel to halt the machine if the speed was over 2 or 3 stitches per second. At 5 sps, the machine might run on for an extra 2 or 3 stitches on its own. You can sand the brake a little thinner to get more free motion before it engages. One of my FS550s has virtually no free motion while another has over 1/2 inch on the pedal. Both turn on very gradually, with no jumps in the speed. My FS-550s have rotary switches, while the newer models have pots. You might want to buy a new model with a pot. Quote Share this post Link to post Share on other sites
Colt W Knight Report post Posted November 30, 2015 (edited) My service has a pot, and I can select anywhere on the dial, and it does that click into place. The slowest setting my machine will sew is between the 350 and 660 hash marks on the dial. It has the pulley that came with motor. If I set mine on 660, it sees pretty fast, but I can feather the pedal and make it walk slowly. Edited November 30, 2015 by Colt W Knight Quote Share this post Link to post Share on other sites
Wizcrafts Report post Posted November 30, 2015 My Family Sew motors have multi-position rotary switches, with resistors coming off the terminals. The highest 4 speed settings are all the same speed, having no further effect on the top speed. The remaining positions (5th and under) each have an obvious effect on the top speed. When I set them at the 350 RPM position and floor the pedal, the walking foot machine turns over at about 2 stitches per second (without a reducer) and the CB4500 at about 1/2 stitch per second, with a 3:1 reducer. Quote Share this post Link to post Share on other sites
kwalk20 Report post Posted November 30, 2015 Something is definitely wrong with mine then. I'm surely calling my dealer. Thanks so much for helping! Quote Share this post Link to post Share on other sites
kwalk20 Report post Posted December 4, 2015 I just wanted to follow up and thank all who tried to offer help. I really appreciate it. The steps Wizcraft gave was enough to inform me that it was definitely an issue with the motor. My dealer is awesome! They promptly sent me a new one and it works like a dream. Now I can make it "walk" like Colt Knight's! Thanks guys! Quote Share this post Link to post Share on other sites
