A high spawner ignore MaxNearbyEntities

1. Start a kreativ world.
2. Write in the chat: /gamerule doMobSpawning false
3. Place a command block with this command:

/setblock ~ ~7 ~ minecraft:mob_spawner 0 replace {EntityId:Zombie,SpawnCount:1,SpawnRange:3,RequiredPlayerRange:124,MinSpawnDelay:10,MaxSpawnDelay:10,MaxNearbyEntities:1}

4. Write in the chat: /time set 18000

Note: If you change ~7 to ~1, all will be ok.