From: "Kardasinski, Milosz" <Milosz.Kardasinski@analog.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Thu, 10 Sep 2020 08:45:36 -0700
Subject: RE: [EE] Microwave Oven Transformers
Thread-Topic: [EE] Microwave Oven Transformers
Thread-Index:
 AQHWWTDTdgLEYlLB80CMUa8aGORcYqkGGn2AgALBCRuAAAiKAIAABfHzgAAGgQCAAARH4YAAEa8AgAAJWtGABN8wPoBTsie4gAAF54CAAASNG4AArcCA
Message-ID:
 <DM5PR03MB3145EC96F467CEDDBA825EBEE7270@DM5PR03MB3145.namprd03.prod.outlook.com>
References:
 <BYAPR02MB4055907B481B158D04EA8552DC600@BYAPR02MB4055.namprd02.prod.outlook.com>
	<CACZQxzPAoxz-PP7x8j7W2kT3yC==RhuioocviAFJfTi=BsSXsg@mail.gmail.com>
	<BYAPR02MB4055730979C10952B0431F7ADC7E0@BYAPR02MB4055.namprd02.prod.outlook.com>
	<alpine.BSF.2.21.9999.2007151808010.43517@nickel.allotrope.net>
	<BYAPR02MB4055E993D92A5B73457E55EEDC7E0@BYAPR02MB4055.namprd02.prod.outlook.com>
	<CANqFfZCNx_VAVqziCevfruVYzPFd2YVWb2E-FbGRyvT_-Ev2VA@mail.gmail.com>
	<BYAPR02MB4055A81DBE35DFFFA66AC00FDC7E0@BYAPR02MB4055.namprd02.prod.outlook.com>
	<CAHD638iaeM-+k1_W1XZyzJDFLR+yHmFFFOw0r_SVk3Y=Pnbeaw@mail.gmail.com>
	<BYAPR02MB40556713C12321B212CCCD54DC7E0@BYAPR02MB4055.namprd02.prod.outlook.com>
	<BYAPR02MB40550FF5F13FD537C6A57E1BDC7D0@BYAPR02MB4055.namprd02.prod.outlook.com>
	<BYAPR02MB405558C5899EDDF3CC37DEA3DC270@BYAPR02MB4055.namprd02.prod.outlook.com>,
	<CAGazNuUGq7hdM7BXW33fU=jbeFMKQcpxaQmnNjpWP9Q3iLj5DQ@mail.gmail.com>
	<BYAPR02MB405580085E3F3EA1BF02A1B3DC270@BYAPR02MB4055.namprd02.prod.outlook.com>
In-Reply-To:
 <BYAPR02MB405580085E3F3EA1BF02A1B3DC270@BYAPR02MB4055.namprd02.prod.outlook.com>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
Content-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
acceptlanguage: en-US
received-spf: Pass (protection.outlook.com: domain of analog.com designates
	148.163.135.77 as permitted sender) receiver=protection.outlook.com;
	client-ip=148.163.135.77; helo=mx0a-00128a01.pphosted.com;
dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
	d=analog.onmicrosoft.com; s=selector2-analog-onmicrosoft-com;
	h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck;
	bh=xTdqvR6YMTatmVq9TIbFwKYbQymSPjdDethu3mF6Dbo=;
	b=EFNbS/cUOchTYTRcfDLDQ38FCF10oySxgAHPNf+pI3ZeBXIXmVHDgLkQ7w5Cj3ouRlDp7MreDWBgFFeASvsXIdyTCiwsj5wXOzercxQW0cIpX/hIeSRWpg7+WQROsdwZxdzQLZDLLDUe/Y53QLP8w95f2jm1cTCeXk75qkV0IpE=
authentication-results: spf=pass (sender IP is 148.163.135.77)
	smtp.mailfrom=analog.com; mit.edu; dkim=pass (signature was verified)
	header.d=analog.onmicrosoft.com;mit.edu; dmarc=pass action=none
	header.from=analog.com;
x-originating-ip: [137.71.220.54]
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-proofpoint-virus-version: vendor=fsecure engine=2.50.10434:6.0.235,
 18.0.687	definitions=2020-09-10_04:2020-09-10,	2020-09-10 signatures=0
x-proofpoint-spam-details: rule=outbound_notspam policy=outbound score=0
	adultscore=0 mlxscore=0	clxscore=1011 bulkscore=0 mlxlogscore=999
 impostorscore=0	suspectscore=0	malwarescore=0 priorityscore=1501 spamscore=0
 lowpriorityscore=0	phishscore=0 classifier=spam adjust=0 reason=mlx
 scancount=1	engine=8.12.0-2006250000 definitions=main-2009100144
x-topics: [EE]
x-mime-autoconverted: from quoted-printable to 8bit by PCH.mit.edu id
	08AFk9Tm028276
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

As you shorten arc length the power drops at a much faster rate on a CC mac=
hine than your typical transformer based unit. It's the fast response of th=
e CC inverter & it's low inductance that are the culprit. The industry solu=
tion to this problem without adding bulk of more inductance is to allow the=
 operator to modify the volt-ampere curve of the power supply. Effectively,=
 the arc force/dig setting modifies the machine output to a constant power =
mode.

-----Original Message-----
From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> On Behalf Of Bob Bl=
ick
Sent: Thursday, September 10, 2020 1:32 AM
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Subject: Re: [EE] Microwave Oven Transformers

There's very little real information available about why inverter-based wel=
ders usually don't work well with cellulosic electrodes. A lot of talk abou=
t open-circuit voltage not being high enough. That's clearly wrong, since t=
he open-circuit voltage only affects the starting of the arc, and the probl=
em here is the arc dying out. Cellulosic electrodes produce a lot of hydrog=
en, which does raise the arc voltage slightly, but it should be well within=
 the welder's capability. I've run the welder on both 120 and 240 volts to =
see if that changes things, and it doesn't, which it would if the arc volta=
ge was the problem. I think the real problem is the current limiting in the=
 welder getting confused by the aggressive percussive arc that cellulosic r=
ods produce.=20

--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.