Unboxing - TIME ELECTRONICS UK - 1048 Voltage/ Current / Loop calibrator

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Electrical Metrology | Measurement Tips & Products | Calibration standards > Electrical Standards & calibration accessories

Kiriakos GR:
Side note:

Littelfuse F100mAL250V first production this made somewhere in 1998.
Several updates from then to now was made for addition of further more compliance's other than VDE & UL & IEC, ROHS this is more recent addition.
I am saying all these because I discovered an opportunity at eBay and I got ten Fuses at retail price of just three recently marketed F100mAL250V.

What I did score this is Littelfuse 217 M100 (production series of 1998), breaking capacity and electrical specifications they are identical to latest batch.
Bellow there is a picture of latest Littelfuse Part numbering system.

My first attempt buying Littelfuse 217 this failed because the seller was having anonymous (Made in China) production of 100mA Fast fuse listed as Littelfuse and even so I did receive ten of them.

In about ten days I am going to actually test what could be influence of fuses at this calibrator day to day usage.
a) Does DC current output gets any noticeable impact from the use of unbranded fuses ?
b) Fuses internal resistance analysis by the use of HIOKI RM3542A about determining how accurate it is resistance specification offered by Littelfuse
c) Fuses internal resistance comparison: Littelfuse VS Generic Fast acting fuse.

At my first topic relative to fuses, I did mention Holly Fuse F100mA, Holly Fuse branding this gained trust of HIOKI Japan, such a decision makes me think, that Holly Fuse in China this is not considered as low-end fuse maker in Asia.

Kiriakos GR:
My comparison of no-name F100mA fuses with Littelfuse 217 M100 this offered to me NEW knowledge.

First find that unbranded fuses these has Cold nominal resistance at range of 120 Milli-Ohm instead of approximately five Ohm that Littelfuse should have, this is a shocking find.

Ten Littelfuse 217 M100 fuses that I got, they do not have finest measuring consistency regarding Cold nominal resistance.
At 16 Celsius only two of ten fuses they come close at the mark of 5.5 Ohm, when most of them they measure from 5.1 Ohm up to 5.4 Ohm.
I am aware that this is old stock and I am going to speculate that in recent years manufacturing process this has improve.

In the positive side of things, 1048 Voltage/ Current calibrator output this was changing when I did test it with both fuses.
Therefore this calibrator circuitry was sensing the difference, but true good news are that this calibrator was automatically adjust inner electronics so output this to be according to LCD display.

In simple English, actual ohms resistance of its fuse was not causing a difference which will drive this calibrator out of it own specifications in the regard of output.
From the other hand, 1048 this has several operating modes, this can be setup as transmitter (active output) and also as receiver (working as multimeter).
For now I did skip this testing of 1048 as receiver and what influence fuses can cause at this operating mode.
When you do select Littelfuse 217 fuses as intended replacement, this will insure max compliance according to 1048 Electronics design (circuitry).

Below are few interesting pictures of my tests. :)
And naturally I will send to trash these 10 unbranded fuses, mostly because I do not trust them for any use.

Kiriakos GR:
It is a first time in my life, in which I was forced to demolish calibration shield so to deal with manufacturing issue relative to proper PCB installation position, so external power port to be usable as expected.

I did use 1048 loop calibrator at significant amount of applications all these months and now this is one of my very favorite tools.

But when I tried to use external power plug I did receive a huge disappointment, male 2.5mm plug of my power supply was unable to maintain stable power connection, while specific power plug was new I did replaced by another new for testing purposes, and the problem did not move away.
I did run out of choices and I had to break calibration shield so to discover the source of the problem.
1048 loop calibrator PCB this is held in place exclusively due single potentiometer mounting nut.
Unfortunately because potentiometer this is far away from power plug, it can not handle well additional mechanical forced needed so male power plug to insert all the way in at the female connector.
Additionally even if male power plug this is inserted all the way, specific on-board connector has issues to firmly hold in place the male connector.

Prior discovering my solution that is addition of plastic spacer so this to kept PCB unmovable, I did try to gently expand diameter of 1048 case hole (power input plug) by assuming that few mm of additional space will aloud male 2.5mm plug to get in position.

In conclusion, my very own workaround it did partially corrected & improved the problem, but it did not solve it 100%.
Times Electronics UK Engineers they should look again at 1048 and of similar ones product design.
Similar power connector over Micro Cal 1030 this is by far better and much superior speaking of mechanical properties.
This product design flaw it is significant and I look forwards to see of how Times Electronics UK will respond on this challenge.