Line Filter for old hedge trimmer - UK Vintage Radio Repair and Restoration Discussion Forum

avocollector · 6th Apr 2015, 3:32 am

I have an old, German make, Hugo Freund Motorheckenschere (mains electric hedge trimmer) model EL-HE-220 - probably from the 50/60's at the latest. Was happily using it when BANG and on disassembly the line filter caps seem to have detonated (as caps sometimes do). They appear to be one cap (O.05 uF) connected between phase and neutral and two caps (2500pf) one connected between the phase and earth and one between neutral and earth. Thumbnail pics below.

As it's still a grunty little machine I'd like to save can you knowledgeable lot tell me if a straight out cap replacement should be OK (assuming motor still ok) and any specific type of caps I must use.

Note the amusingly helpful note at the bottom of the nameplate 'Nicht benutzen bei regen = Don't use in the rain'. Sadly Hugo Freund has been taken over and closed in 2005

Radio Wrangler · 6th Apr 2015, 7:15 am

The symbol next to the helpful hint at the bottom right is the FTZ rf interference suppression approval mark.

David

julie_m · 6th Apr 2015, 7:39 am

That just looks like a standard delta-capacitor with a 50 nF capacitor working in class X and two 2.5 nF capacitors working in class Y. Nearest modern preferred values available would be 47 nF and 2.2 nF. Of course, the hedge trimmer will work perfectly without these capacitors -- but other people's MW, LW and SW radios might not!

mark pirate · 6th Apr 2015, 8:46 am

Maybe the cap has been replaced before, I see a date code of 4/67 on it.
I notice the mains voltage is 220v, I expect running on 240v finally killed off the cap!

Mark

David G4EBT · 6th Apr 2015, 8:49 am

Unusually these days, Maplin of all people have what you need, and not too expensive either!

A Delta Suppression Filter, consisting of one 0.1uF, plus two .047 plus 2.2M resistor:

http://www.maplin.co.uk/p/delta-supp...n-filter-rg21x

(£3.29).

julie_m · 6th Apr 2015, 9:01 am

Interference suppressor capacitors work by absorbing the energy present in the noise spikes on the mains, converting it to heat. The relentless stream of noise bursts from the brushes of a series-wound motor will eventually kill them off (often with an explosion which is theatrical enough to persuade the owner to replace the entire appliance; when in reality, a cheap and easily-replaceable part is all that has failed).

David G4EBT · 6th Apr 2015, 10:50 pm

Ooops, sorry - no Maplin in NZ, so that wasn't much help as I don't think they send overseas.

Right component - wrong hemisphere!

Billy T · 9th Apr 2015, 11:36 am

Quote:

Originally Posted by avocollector

They appear to be one cap (O.05 uF) connected between phase and neutral and two caps (2500pf) one connected between the phase and earth and one between neutral and earth.

JayCar sell metallised polypropylene caps in 0.047 and 0.022 values rated for mains applications. I use them to replace the old RIFA caps in industrial & commercial metal detectors when they blow up. JayCar's shop is at 76-80 Adelaide Road, Mt Cook, Wellington.

You can fit them in easily, and if you get their WH-5520 Heatshrink Tubing assortment pack, for less than $20 you'll have plenty of options for insulation and protection, and a wide range of colours and sizes for future use.

Cheers

Billy

avocollector · 12th Apr 2015, 4:51 pm

Many and great thanks to all of you for advice, help and ideas - all greatly appreciated and a great help for this less familiar area. Also special thanks to Billy T for the local advice - perhaps now I'll be able to get the darned thing off my workbench - LOL.

keithinuk · 12th Apr 2015, 6:15 pm

I have one hiding in the shed, I think the motor has had its day, I did try to find a replacement but to no avail.
It is a Black & Decker, in its original box, I did see an advert for it once, but never seen another one.
One sided blade, aluminium body from the 50's I think it is.

6th Apr 2015, 3:32 am	#1
avocollector Heptode Join Date: Jul 2010 Location: Wellington, New Zealand. Posts: 653	Line Filter for old hedge trimmer I have an old, German make, Hugo Freund Motorheckenschere (mains electric hedge trimmer) model EL-HE-220 - probably from the 50/60's at the latest. Was happily using it when BANG and on disassembly the line filter caps seem to have detonated (as caps sometimes do). They appear to be one cap (O.05 uF) connected between phase and neutral and two caps (2500pf) one connected between the phase and earth and one between neutral and earth. Thumbnail pics below. As it's still a grunty little machine I'd like to save can you knowledgeable lot tell me if a straight out cap replacement should be OK (assuming motor still ok) and any specific type of caps I must use. Note the amusingly helpful note at the bottom of the nameplate 'Nicht benutzen bei regen = Don't use in the rain'. Sadly Hugo Freund has been taken over and closed in 2005 Attached Thumbnails

6th Apr 2015, 7:15 am	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Line filter for old hdge trimmer The symbol next to the helpful hint at the bottom right is the FTZ rf interference suppression approval mark. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

6th Apr 2015, 7:39 am	#3
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Line filter for old hdge trimmer That just looks like a standard delta-capacitor with a 50 nF capacitor working in class X and two 2.5 nF capacitors working in class Y. Nearest modern preferred values available would be 47 nF and 2.2 nF. Of course, the hedge trimmer will work perfectly without these capacitors -- but other people's MW, LW and SW radios might not! __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

6th Apr 2015, 8:46 am	#4
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Line filter for old hdge trimmer Maybe the cap has been replaced before, I see a date code of 4/67 on it. I notice the mains voltage is 220v, I expect running on 240v finally killed off the cap! Mark

6th Apr 2015, 8:49 am	#5
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,767	Re: Line filter for old hdge trimmer Unusually these days, Maplin of all people have what you need, and not too expensive either! A Delta Suppression Filter, consisting of one 0.1uF, plus two .047 plus 2.2M resistor: http://www.maplin.co.uk/p/delta-supp...n-filter-rg21x (£3.29). __________________ David. BVWS Member. G-QRP Club member 1339.

6th Apr 2015, 9:01 am	#6
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Line filter for old hdge trimmer Interference suppressor capacitors work by absorbing the energy present in the noise spikes on the mains, converting it to heat. The relentless stream of noise bursts from the brushes of a series-wound motor will eventually kill them off (often with an explosion which is theatrical enough to persuade the owner to replace the entire appliance; when in reality, a cheap and easily-replaceable part is all that has failed). __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

6th Apr 2015, 10:50 pm	#7
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,767	Re: Line Filter for old hedge trimmer Ooops, sorry - no Maplin in NZ, so that wasn't much help as I don't think they send overseas. Right component - wrong hemisphere! __________________ David. BVWS Member. G-QRP Club member 1339.

12th Apr 2015, 4:51 pm	#9
avocollector Heptode Join Date: Jul 2010 Location: Wellington, New Zealand. Posts: 653	Re: Line Filter for old hedge trimmer Many and great thanks to all of you for advice, help and ideas - all greatly appreciated and a great help for this less familiar area. Also special thanks to Billy T for the local advice - perhaps now I'll be able to get the darned thing off my workbench - LOL.

12th Apr 2015, 6:15 pm	#10
keithinuk Retired Dormant Member Join Date: Mar 2011 Location: Hertfordshire, UK. Posts: 208	Re: Line Filter for old hedge trimmer I have one hiding in the shed, I think the motor has had its day, I did try to find a replacement but to no avail. It is a Black & Decker, in its original box, I did see an advert for it once, but never seen another one. One sided blade, aluminium body from the 50's I think it is.