Anti-pumping relay in circuit breaker control schemes

[Hill F.]

Typically, the anti-pumping relay Y in cb control schemes picks-up through an auxiliary contact of the MR motor relay or of the spring-charge status mechanism (for example: see control diagram for Square D model VAD-3 vacuum breaker).
Question: what is the logic behind this implementation - would it not be more reasonable to pick-up the Y relay through a 52a n/o auxiliary switch of the breaker itself?

 

[zog]

How would that stop the breaker from reclosing?

 

[Hill F.]

How would that stop the breaker from reclosing?

Explanation: Following initial breaker closing, 52y will pick up through a n/o 52/a contact (instead of the n/o 52MR contact) and seal itself in through its own (now closed) n/o contact.
52y stays energized as long as 52cs control switch is held in "Close Breaker" position.
Should the breaker trip while 52cs is still in "Close Breaker" position: 52y's (now open) n/c contact in the 52 close circuit prevents breaker reclosing.
Eons ago I was involved in commissioning air-blast breakers, and I believe that anti-pumping was implemented just this way i.e. 52y picked up via a n/o 52a auxiliary switch when 52 went "on", indepedent of air pressure. So this begs the question: why is 52y pickup implemented differently for spring-operated breakers i.e. why should 52y pickup depend upon spring charge status, instead of 52 on/off status?

 

[SG-1]

Explanation: Following initial breaker closing, 52y will pick up through a n/o 52/a contact (instead of the n/o 52MR contact) and seal itself in through its own (now closed) n/o contact.
52y stays energized as long as 52cs control switch is held in "Close Breaker" position.
Should the breaker trip while 52cs is still in "Close Breaker" position: 52y's (now open) n/c contact in the 52 close circuit prevents breaker reclosing.
Eons ago I was involved in commissioning air-blast breakers, and I believe that anti-pumping was implemented just this way i.e. 52y picked up via a n/o 52a auxiliary switch when 52 went "on", indepedent of air pressure. So this begs the question: why is 52y pickup implemented differently for spring-operated breakers i.e. why should 52y pickup depend upon spring charge status, instead of 52 on/off status?

The initial condition is spring charged & breaker open. When the breaker closes by control switch or remote command the closing spring is discharged. The motor begins running to recharge the spring, this takes several seconds. If the breaker tripped or failed to close the Y-coil will pick up & seal itself in if the close signal remains energized or returns before the closing spring is fully charged.

The breaker is prevented from attempting to close until the closing spring is fully charged & the mechanism is set. It would not have the mechanical energy to meet the Close & Latch rating with a partially charged closing spring. This is why the spring charge status governs the Y-coil.

To use this breaker with a 79 it must successfully close & recharge it's closing spring. If a trip occcurs, then the reclosing relay can close the breaker back in say 10 cycles or so, however fast the mech can operate. Then the spring re-charge time ( about 6 seconds ) kicks in. It been a long time since I had to do a timing test for this, so I could be off a few cycles. My experience is with Westinghouse breakers.

 

[ATSman]

I tend to agree with SG-1.
Further proof of how this logic works is see in these Westinghouse LVCB's
Type DS and SPB-100.
The SR coil (spring release) is the closing coil in the Pics:

 

[Hill F.]

Let us consider a "classic" c.b. control circuit e.g. fig. 2.6 (page 21) in this guide. In this circuit, 52y is enabled via 52aa i.e. the "ready/unready" condition of 52's operating mechanism is irrelevant to operation of 52y.
An electrical interlock for "52 closing mechanism not ready" is (purposely?) absent from the circuit, but this oversight can be remedied by addition of a "52 ready for operation" contact directly into the 52/cc circuit, e.g. 52/mr n/c contact in the diagram here (page 11).
My conclusion: the advantage of using 52/mr to control 52y is still unclear (at least to myself).
N.B. sincere apologies for delay in continuing the discussion.

 

[SG-1]

Let us consider a "classic" c.b. control circuit e.g. fig. 2.6 (page 21) in this guide. In this circuit, 52y is enabled via 52aa i.e. the "ready/unready" condition of 52's operating mechanism is irrelevant to operation of 52y.
An electrical interlock for "52 closing mechanism not ready" is (purposely?) absent from the circuit, but this oversight can be remedied by addition of a "52 ready for operation" contact directly into the 52/cc circuit, e.g. 52/mr n/c contact in the diagram here (page 11).
My conclusion: the advantage of using 52/mr to control 52y is still unclear (at least to myself).
N.B. sincere apologies for delay in continuing the discussion.

If you were to use a breaker "b" Aux contact the Y-Coil would race the Close Coil when a close signal was energized & the mech was ready. Using the motor limit switch avoids this undesirable condition.

I cannot see the guide.