X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 19 Oct 2012 08:28:57 -0400 Message-ID: X-Original-Return-Path: Received: from mail-vb0-f52.google.com ([209.85.212.52] verified) by logan.com (CommuniGate Pro SMTP 6.0c2) with ESMTPS id 5831768 for lml@lancaironline.net; Thu, 18 Oct 2012 15:19:00 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.212.52; envelope-from=edmartintx@gmail.com Received: by mail-vb0-f52.google.com with SMTP id k17so7844417vbj.25 for ; Thu, 18 Oct 2012 12:18:23 -0700 (PDT) MIME-Version: 1.0 Received: by 10.58.203.161 with SMTP id kr1mr7901818vec.35.1350587903803; Thu, 18 Oct 2012 12:18:23 -0700 (PDT) Received: by 10.58.181.65 with HTTP; Thu, 18 Oct 2012 12:18:23 -0700 (PDT) In-Reply-To: References: X-Original-Date: Thu, 18 Oct 2012 15:18:23 -0400 X-Original-Message-ID: Subject: Re: [LML] Re: TCM 60A alternator--diodes From: ED MARTIN X-Original-To: Lancair Mailing List Content-Type: multipart/alternative; boundary=047d7beb9a4e3e826904cc5a4050 --047d7beb9a4e3e826904cc5a4050 Content-Type: text/plain; charset=ISO-8859-1 * But the Alternator has six diodes visible ..... How does your formula apply in this case ???* On Thu, Oct 18, 2012 at 12:41 PM, Wolfgang wrote: > You may want to re-think those diodes. > Those 50A diodes are NOT suitable for a 100 amp alternator. > They are only good for 50 x sqr3 = 86.6 amps > . . . and then only if you have good heat sinks on those diodes. > > Wolfgang > > ----- Original Message ----- From: "Paul Miller" > To: > Sent: Wednesday, October 17, 2012 8:43 AM > Subject: TCM 60A alternator--diodes > > > My primary alternator is original equipment TCM 60A alternator with 660 > hours. It should have been inspected at 500 hours but I deferred that. > This note suggests that the diodes get a check during that 500H > inspection. My secondary is a B&C 20A which was just replaced this year > after 600+ hours after some windings failed. I have had a lot of radio > noise but nothing so bad as to take steps to fix it. I had no idea that my > primary was only partially functioning. On this last trip from Calgary to > Texas and onto Florida, my primary was noted to have Zero output while > taxiing for takeoff at Midland TX. I flew using the secondary to charge > both busses for the two legs into Florida. After some testing I ruled out > the primary B&C regulator. Today, I tested the field resistance (15 ohms, > acceptable range should be 12-100 ohms) which was perfect. The field is > the rotor on this unit. I decided to pull the housing and check brushes > which were found to be almost perfect (90% remaining after 660 hours). > > The stator was uniform in color and not shorted. It pulls out easily for > inspection. The body of the alternator was not removed from the engine > making this test very fast and easy. A quick check revealed all six diodes > (two each for the three phases) had failed. Everything else was in > excellent condition. This unit is similar to the standard Delco Remy 10Si > alternator and shares many parts. The diode replacement from Aircraft > Spruce is almost $200. The new alternator is about $1400. A repair with > new rotor is about $500 including shipping and labor from a reputable shop > I spoke with. > > The diode assembly was sourced at my local shop with a spare set of > brushes for $20 total. These are 50A diodes (50A x 6 diodes) which is a > robust replacement satisfactory for even the 100A alternator. I had to > remove the B+ stud from the old diode assembly and press it into > replacement diode package. The re-assembly took about 20 minutes and it > fired up with 10A charge on low engine idle. This is much higher charge at > low idle than I can ever recall. > > This means that I've been flying for some time with less than 6 diodes. > I probably was flying on one or two phases and getting some radio noise > from the failed diodes. This may have been ongoing for years. Testing > diodes as part of a 500H inspection is simple to accomplish and guarantees > some margin for partial failure. I have photos I can markup and add for > reference in a follow up email. Here are the excellent contacts who helped > today: > > 1) TCM technical support 888.826.5465 Provided technical guidance and > emailed me the alternator service manual in PDF form (48p) without > hesitation. > 2) Bill at B&C Specialty, 316-283-8000, always helpful. Provided testing > procedure for regulator and the following reference for repair. > 3) Aircraft Systems, Rockford IL, 815-399-0225 TCM alternator repair > specialists > 4) Rupp Auto, New Smyrna Beach, bench testing, parts and expert on 10Si > alternators and repairs > > It took about a day to get it done but the cost was right and I kept all > my original parts and did not need to remove or ship the alternator. > > Paul > Legacy, Spruce Creek. > > > -- > For archives and unsub http://mail.lancaironline.net:** > 81/lists/lml/List.html > --047d7beb9a4e3e826904cc5a4050 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable =A0=A0=A0=A0 But the Alternator has six diodes visible .....= How does your formula apply in this case ???

On Thu, Oct 18, 2012 at 12:41 PM, Wolfgang <Wo= lfgang@micom.net> wrote:
You may want to re-think those diodes= .
Those 50A diodes are NOT suitable for a 100 amp alternator.
They ar= e only good for 50 x sqr3 =3D 86.6 amps
. . . and then only if you have good heat sinks on those diodes.

Wol= fgang

----- Original Message ----- From: "Paul Miller" <= ;pjdmiller@gmail.c= om>
To: <lml@lanc= aironline.net>
Sent: Wednesday, October 17, 2012 8:43 AM
Subje= ct: TCM 60A alternator--diodes


My primary alternator is original= equipment TCM 60A alternator with 660 hours. =A0It should have been inspec= ted at 500 hours but I deferred that. =A0This note suggests that the diodes= get a check during that 500H inspection. =A0My secondary is a B&C 20A = which was just replaced this year after 600+ hours after some windings fail= ed. =A0I have had a lot of radio noise but nothing so bad as to take steps = to fix it. =A0I had no idea that my primary was only partially functioning.= =A0On this last trip from Calgary to Texas and onto Florida, my primary wa= s noted to have Zero output while taxiing for takeoff at Midland TX. =A0 I = flew using the secondary to charge both busses for the two legs into Florid= a. =A0After some testing I ruled out the primary B&C regulator. =A0Toda= y, I tested the field resistance (15 ohms, acceptable range should be 12-10= 0 ohms) which was perfect. =A0The field is the rotor on this unit. =A0I dec= ided to pull the housing and check brushes which were found to be almost pe= rfect (90% remaining after 660 hours).

The stator was uniform in color and not shorted. =A0 It pulls out easil= y for inspection. =A0 The body of the alternator was not removed from the e= ngine making this test very fast and easy. =A0A quick check revealed all si= x diodes (two each for the three phases) had failed. =A0Everything else was= in excellent condition. =A0This unit is similar to the standard Delco Remy= 10Si alternator and shares many parts. =A0 The diode replacement from Airc= raft Spruce is almost $200. =A0The new alternator is about $1400. =A0 A rep= air with new rotor is about $500 including shipping and labor from a reputa= ble shop I spoke with.

The diode assembly was sourced at my local shop with a spare set of bru= shes for $20 total. =A0These are 50A diodes (50A x 6 diodes) which is a rob= ust replacement satisfactory for even the 100A alternator. =A0I had to remo= ve the B+ stud from the old diode assembly and press it into replacement di= ode package. =A0The re-assembly took about 20 minutes and it fired up with = 10A charge on low engine idle. =A0This is much higher charge at low idle th= an I can ever recall.

This means that I've been flying for some time with less than 6 dio= des. =A0 I probably was flying on one or two phases and getting some radio = noise from the failed diodes. =A0 This may have been ongoing for years. =A0= Testing diodes as part of a 500H inspection is simple to accomplish and gua= rantees some margin for partial failure. =A0 I have photos I can markup and= add for reference in a follow up email. =A0Here are the excellent contacts= who helped today:

1) TCM technical support 888.826.5465 Provided technical guidance and e= mailed me the alternator service manual in PDF form (48p) without hesitatio= n.
2) Bill at B&C Specialty, 316-283-8000, always helpful. =A0Provid= ed testing procedure for regulator and the following reference for repair.<= br> 3) Aircraft Systems, Rockford IL, 815-399-0225 TCM alternator repair specia= lists
4) Rupp Auto, New Smyrna Beach, bench testing, parts and expert on= 10Si alternators and repairs

It took about a day to get it done but= the cost was right and I kept all my original parts and did not need to re= move or ship the alternator.

Paul
Legacy, Spruce Creek.


--
For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html

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