Convergence time on stack (N4032F) when master is failed.

Have an issue with convergence when the master is failed (power pulled) from our core stack. The core also runs routing within the LAN. I was testing by pinging the Core stacks next hop from a port on the access stack. 

When the masters power was pulled it took 1m45sec for the network to converge and pings to start again. Is this normal as it seems way to slow?

Hardware involved is core stack of 2 N4032F and access stack of 4 N1548, connections between them is port channel via 10Gb SPF+ 1 from each N1548, so each N4032F has 2 connection for the N12548 stack.