Hi Chris,
Thanks for your comments in
detail.
1.
The casing melting/distortion did occur before testing;
2.
The insulation was not melting, it was intenerated when the melting
plastic force to the side and surface of the device, it is the cause of
deformation for device’s side. Besides, our materials used for this plastic
part was raw material mixed with carbon black and the rate is 2%. Therefore,
whether it induces the test failure?
BTW, we have tried to clear up
the breakdown surface and then re-test it by the same test conditions, the test
result is OK. Whether the test failure relate to the insulation surface
roughness or not?
Thanks and best regards,
Justin Wu
Utilux South China Ltd
Phone: +86-755-2850 7521
Fax: +86-755-2850
0927
From:
TGAsia [mailto:
Sent: Thursday, November 27, 2008
12:05 PM
To:
Subject: [TGAsia] 答复: Re: [TGAsia] Hi-Pot
Test Failure (2250V /3S/3mA)
Hi Justin
I agree with Jeffrey's comments but also add:
(1) When testing, does casing melting/distortion occur before or after the breakdown point? If the
device is overheating beyond the maximum operating temperature of the
insulation materials, this may be the root cause of failure. Keep in mind
resistance induced heating has a progressive effect.
(2) Is the wire gage sufficient to carry the test current?
Sometimes the current required for testing is greater than the designed
capacity of the device and may need changing the test criteria/method (to suit
the design) or upgrading the wire gage/wire insulation.
(3) As Jeffrey noted, any protrusions of the wire/crimp can
induce failure. Another potential problem is over-crimping if the
cross-sectional area (of the crimp) is reduced below the current carrying
capacity of the conductors.
In practical terms, test the wire, wire with terminal
installed and then finished connector to check for dielectric breakdown and
over-heating. When and why is the insulation melting?
Good luck.
C.B. Katzko 嘉仕高
Research + Development
Meadville Group
e-mail [log in to unmask]
tel +86 21 3774 7528
fax +86 21 3774 7590
mobile +86 13817362590
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|
"Liang,
Jeffrey" <[log in to unmask]>
2008/11/27 11:46
|
|
Justin,
I would like to propose you to try/look at
things below:
1- Please do hi-pot test on raw cable/wires
itself to see if it can withstand 2250V/3S/3mA.
2- Please inspect the crimped terminal and
wire brush after crimping to see if there is any bur created by crimping tool.
You know the bur would cause HI-POT failure. Also, please make wire brush is as
trim as possible.
Hope it helps.
Thanks,
Jeffrey Liang
86-757-28385503
From:
TGAsia [mailto:[log in to unmask]]
On Behalf Of justin
Sent: Thursday, November 27, 2008 11:35 AM
To:
Subject: Re: [TGAsia] Hi-Pot Test Failure (2250V/3S/3mA)
Hi Sir,
The breakdown voltage is 38KV
as shown in the raw materials data sheet provided by supplier.
Thanks and best regards,
Justin Wu
Utilux South China Ltd
Phone: +86-755-2850 7521
Fax:
+86-755-2850 0927
E-mail Address: [log in to unmask]
www.utiluxchina.com
From:
TGAsia [mailto:[log in to unmask]]
On Behalf Of Bo Wu
Sent: Wednesday, November 26, 2008 6:25 PM
To:
Subject: Re: [TGAsia] Hi-Pot Test Failure (2250V/3S/3mA)
看看绝缘材料的耐压
-----原始邮件-----
发件人: justin
<[log in to unmask]>
发送时间:
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主题: Re: [TGAsia] Hi-Pot Test
Failure (2250V/3S/3mA)
Hi All,
Good afternoon!
I am currently having face the
Hi-Pot test failure with 2250V/3mA/3S problem and that the failure rate about
0.6%. The details see attached files shown. For this problem, we have sought
for a lot of solution, but still failed at final. So which expert can share
your experience to me on this? (Whether the test condition too tight?)
Thanks in advance!
Best regards,
Justin Wu
Utilux South China Ltd
Phone: +86-755-2850 7521
Fax:
+86-755-2850 0927
E-mail Address: [log in to unmask]
www.utiluxchina.com