F
Fritz Schlunder
- Jan 1, 1970
- 0
Electronic Swear said:The DC motor is operated at (rectified) 220Vac.
It is for food juicer. We don't want to use current
sensing because the motor start-up current is very large.
Similiar to what the current at lock rotor. As a result,
current monitoring is not a very good method. Even the motor
will be over-loading for a short moment when the user is putting
a very hard / big food for juicing at the beginning.
The current will be very large at the beginning but will drop
to a suitable value. However, we cannot cut-off the motor source
because of over-current. We will allow the motor operating at a
very high current for a short time, several seconds.
The motor is for masss production and look for safety protection
as well. If use fuse on protection, it is very inconvenient for
exchange. We want some active protection rather than passive components.
I will try for using the SCRs at the bridge rectifying.
However, the current rating of the SCR just 25A is enough or not?
And any detail on snubber capacitor?
Hmm... Mass production... DC motor from rectified 220Vac... Food
juicer... 40A for two seconds overload current...
Is this a consumer product?
I live in a 120Vac country, but allot of household circuits have circuit
breakers of only 15Amps or sometimes 25A. I imagine in 220Vac countries
they would use similar or smaller circuit breakers. If this is a consumer
product I should imagine if you let the motor draw 40A for two seconds in
allot of instances it will trip the household circuit breaker... Am I
missing something here?