Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!
-
Why 400 Hz in mainframes?
400Hz has proved to be best frequency... actually 415Hz when my memory serves me right. 1000 Hz is too high. Transformer coils are actually heavy duty chokes...so to say,...high resistance to high frequency. I complete agree with you that other companies also made their own supplies. I...- JanH
- Post #34
- Forum: Electrical Engineering general discussion
-
Why 400 Hz in mainframes?
Hi, I see that there is an idea that 400 Hz powersupplies were used because there was a surplus of them. Well, IBM mainframes were using brand new , specially designed powersuplies, so no surplus what so ever. 400 Hz in planes is for the same reason as in Mainframes. Smaller transformers...- JanH
- Post #32
- Forum: Electrical Engineering general discussion
-
Why 400 Hz in mainframes?
peebee, The idea is that at 60Hz you have a 16.6 mS between top-top voltage and at 400 Hz only 2.5 mS. A DC voltage under load will go down in voltage when the AC voltage is in the process of going through zero (alternate it polarity) This is simple because the AC voltage is lower that the DC...- JanH
- Post #25
- Forum: Electrical Engineering general discussion
-
Why 400 Hz in mainframes?
Hi, 400Hz is easier to create the - 0.85V (Logical 1) and the -1.85V (logical 0) from. These powersuplies were capable of supplying 100-200 Amps and stayed within a few mV stable. Try that with 60HZ.... The disk motors run on either 1 phase 50/60Hz or 3 phase 60Hz and when I remember...- JanH
- Post #22
- Forum: Electrical Engineering general discussion
