angle grinder soft start?

[johnpalmer1963]

Hi all, bought a few old power tools that need fixing, in one of them (a Titan 9" angle grinder) the part in the picture has burnt out, it says on it AOL 230v-50hz DS12A, I have been told it is a soft starter and have tried everywhere to source it but with no luck, question is if one of these can't be sourced is there something else that can be used, thanks in advance

 

[chopnhack]

Hi all, bought a few old power tools that need fixing, in one of them (a Titan 9" angle grinder) the part in the picture has burnt out, it says on it AOL 230v-50hz DS12A, I have been told it is a soft starter and have tried everywhere to source it but with no luck, question is if one of these can't be sourced is there something else that can be used, thanks in advance

Well unfortunately all I found was that the tool is made in China(part 95). There is a possibility though of picking up another similar tool that would have soft start and scavenging it for the part. That being said, it would probably be cheaper to replace. Maybe someone else will come along with better success. In the states we have a company called Harbor Freight, see their website for many similar looking tools from China. Notice that the body will be the same, just the color or the plastic may vary sometimes.

Best of luck.

 

[johnpalmer1963]

Thanks chopnhack, I did contact a parts company on the net and they said it was Chinese and it may be difficult to source it, it may be a silly question but if the part was omitted would the motor self destruct?

 

[KJ6EAD]

Where is the part mounted and how is it connected?

 

[chopnhack]

Thanks chopnhack, I did contact a parts company on the net and they said it was Chinese and it may be difficult to source it, it may be a silly question but if the part was omitted would the motor self destruct?

I would rather doubt that, its job is to limit the inrush current or voltage and slowly ramp up so that the tool doesn't jar your hand. Without the part, does the tool operate? I would think it would be an open circuit at this point. As @KJ6EAD mentioned, it would be helpful for a picture of the board, both sides. See the resource for photo submission of boards.

 

[johnpalmer1963]

There isn't a board inside, it fits directly between the switch and the motor as per the pic.

 

[chopnhack]

There isn't a board inside, it fits directly between the switch and the motor as per the pic.

I see it now. So at this point the unit does not turn on correct? I assume that the soft start burn out (thus opening the circuit).

 

[johnpalmer1963]

That's correct, it has burned out and the circuit is open, as there are many types of these angle grinders and the 9" type are all soft start even if this part cannot be sourced then there must be something else to solder inline that will do the job

 

[chopnhack]

That's correct, it has burned out and the circuit is open, as there are many types of these angle grinders and the 9" type are all soft start even if this part cannot be sourced then there must be something else to solder inline that will do the job

Sorry John, after looking at the schematics for three different models offered by Harbor Freight I have had no luck in finding a part like yours, unless its hidden in the switch body itself. As a junior here, I have helped you as far as I can. I hope others will come by soon to assist you. The next thing I would try if it was my tool, would be to jumper the burnt out device. But I would wait for more seasoned advice

 

[Arouse1973]

It's most likely a bespoke soft start module with Triac and controller built in. I think you may have trouble finding a spare part. Unless you by another second hand grinder with a different fault.
Adam

 

[Arouse1973]

Thinking about it, it might be just an NTC. Are there any marking on the device?
Adam

 

[johnpalmer1963]

Hi Adam, no special markings on the grinder except where it says Titan power tools (UK) ltd lol, on the part that burnt out there is a little schematic showing where the part fits but nothing special apart from what else it says is in the first post in this thread, cheers

 

[KJ6EAD]

I believe it's a combination NTC thermistor and PTC thermal fuse. See references:

http://www.ohioelectricmotors.com/what-are-thermistors-and-how-do-they-limit-inrush-current-702

http://en.m.wikipedia.org/wiki/Inrush_current_limiter

 

[johnpalmer1963]

Can you actually buy this as a unit like in the picture or would it be necessary to buy the parts separately and make it up?

 

[KJ6EAD]

You can buy it as a single unit but I've not seen one in that package. Most are in the form of a disk.

Epcos make some that combine both features.

http://www.epcos.com/blob/173714/download/6/thermofusevaristors-pb.pdf

 

[johnpalmer1963]

Farnell sell something like this here

http://uk.farnell.com/Search?storeId=10151&catalogId=15001&langId=44&sf=0&st=thermo fuse

are these correct? There is only one that says voltage @ 230v, this one on the page - B72214T2171K105 would this be suitable? thanks

 

[Finn]

I have the same problem - I found the part for sale on a French website as a spare for a chainsaw (tronconneuse) but they're out of stock at present
http://sav03.fr/boutique/fks-2200-a...s-florabest-serie-fks-2200-2000000004631.html
did your Farnell solution work?

 

[KTW]

I think it's an SCR but I don't know which one.

soft starting electric motors in power tools—phase control, sometimes referred to as electronic, and mechanical. In the phase control approach, a thyristor, such as a triac or silicon controlled rectifier (SCR) is used to switch power to the motor. When the motor is first started, turn-on of the thyristor is delayed a predetermined number of degrees out of each half cycle of the AC waveform. For example, turn-on of the thyristor might be delayed thirty degrees during each half cycle of the AC waveform so that the thyristor is not turned on in each half cycle until thirty degrees into the half cycle. After the motor reaches a predetermined speed, or an appropriate period of time elapses, the delayed turn-on of the thyristor ceases and the thyristor is turned-on at the beginning of each half-cycle.

 

[KTW]

You can contact this company and ask for parts, they sell Titan.

http://www.screwfix.com/jsp/help/contactus.jsp

 

[Darren Dillon]

Hi there - I may be slightly late here but I recently have been looking for one of these parts for a Florabest chainsaw. The part can be bought from Einhill Uk. Part Number 443057001046. They quoted me £13.58 and £3.50 delivery.